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Sample records for reactor related problems

  1. Hydrogen problems related to reactor accidents

    International Nuclear Information System (INIS)

    Bujor, A.

    1993-09-01

    At reactor accidents, the combustion of hydrogen causes pressure and temperature transients which pose supplementary loads in containment. In certain conditions, they could reach hazardous levels and impair the integrity of the containment and the operability of the safety systems. The mechanisms of chemical reactions specific for the hydrogen-oxygen system are presented. Conditions in which combustion can occur and the various combustion modes, including the transition to detonation are also described. The related safety aspects and mitigation methods are discussed. Examples for particular applications and safety approaches for various types of reactors, included those promoted for the advanced reactors are also given. Presentation of the experimental research completed at AECL-Research, Whiteshell Laboratory is given, where the multi-point ignition effects for constant volume and for vented combustion of dry hydrogen-air mixtures in various geometries have been investigated. Various aspects of modelling and simulation of hydrogen combustion are discussed. The adaptations and the new models implemented in the codes VENT and CONTAIN, aimed to widen the simulation capabilities of hydrogen combustion models are described. The capabilities and limitations of the modelling assumptions of these two codes are also evaluated. (EG) (11 tabs., 39 ills., 82 refs.)

  2. Tritium-related materials problems in fusion reactors

    International Nuclear Information System (INIS)

    Hickman, R.G.

    1976-01-01

    Pressing materials problems that must be solved before tritium can be used to produce energy economically in fusion reactors are discussed. The following topics are discussed: (1) breeding tritium, (2) recovering bred tritium, (3) containing tritium, (4) fuel recycling, and (5) laser-fusion fueling

  3. Safety problems relating to plutonium recycling in light water reactors

    International Nuclear Information System (INIS)

    Devillers, C.; Frison, J.M.; Mercier, J.P.; Revais, J.P

    1991-01-01

    This paper describes the specific nature, as regards safety, of the mixed oxide (MOX) fuel cycle, with the exception of safety problems relating to the operation of nuclear power plants. These specific characteristics are due mainly to the presence of plutonium in fresh fuel and to the higher plutonium and transuranic element content in spent fuel assemblies. The fuel cycle steps analysed here are the transport of plutonium oxide, the manufacture of MOX fuel assemblies, the transport of fresh and spent fuel assemblies and the processing of spent fuel assemblies. (author) [fr

  4. Safety problems relating to plutonium recycling in light water reactors

    International Nuclear Information System (INIS)

    Devillers, C.; Frison, J.M.; Mercier, J.P.; Revais, J.P.

    1991-01-01

    This paper describes the specific nature, as regards safety, of the mixed oxide (MOX) fuel cycle, with the exception of safety problems relating to the operation of nuclear power plants. These specific characteristics are due mainly to the presence of plutonium in fresh fuel and to the higher plutonium and transuranic element content in spent fuel assemblies. The fuel cycle steps analysed here are the transport of plutonium oxide, the manufacture of MOX fuel assemblies, the transport of fresh and spent fuel assemblies and the processing of spent fuel assemblies

  5. The use of genetic algorithms with niching methods in nuclear reactor related problems

    International Nuclear Information System (INIS)

    Sacco, Wagner Figueiredo

    2000-03-01

    Genetic Algorithms (GAs) are biologically motivated adaptive systems which have been used, with good results, in function optimization. However, traditional GAs rapidly push an artificial population toward convergence. That is, all individuals in the population soon become nearly identical. Niching Methods allow genetic algorithms to maintain a population of diverse individuals. GAs that incorporate these methods are capable of locating multiple, optimal solutions within a single population. The purpose of this study is to test existing niching techniques and two methods introduced herein, bearing in mind their eventual application in nuclear reactor related problems, specially the nuclear reactor core reload one, which has multiple solutions. Tests are performed using widely known test functions and their results show that the new methods are quite promising, specially in real world problems like the nuclear reactor core reload. (author)

  6. Fusion reactor problems

    International Nuclear Information System (INIS)

    Carruthers, R.

    It is pointed out that plasma parameters for a fusion reactor have been fairly accurately defined for many years, and the real plasma physics objective must be to find the means of achieving and maintaining these specifiable parameters. There is good understanding of the generic technological problems: breading blankets and shields, radiation damage, heat transfer and methods of magnet design. The required plasma parameters for fusion self-heated reactors are established at ntausub(E) approximately 2.10 14 cm -3 sec, plasma radius 1.5 to 3 m, wall loading 5 to 10 MW cm -2 , temperature 15 keV. Within this model plasma control by quasi-steady burn as a key problem is studied. It is emphasized that the future programme must interact more closely with engineering studies and should concentrate upon research which is relevant to reactor plasmas. (V.P.)

  7. Target reactor development problems

    International Nuclear Information System (INIS)

    Lathrop, K.D.; Vigil, J.C.

    1977-01-01

    Target-blanket design studies are discussed for an accelerator-breeder concept employing a linear accelerator in conjunction with a modified conventional power reactor to produce both fissile fuel and power. The following problems in target and blanket system design are discussed: radiation damage, heat removal, neutronic design, and economics

  8. Light-water reactors. Safety problems and related studies in France

    International Nuclear Information System (INIS)

    Lelievre, J.

    1975-01-01

    The program of theoretical and experimental studies developed by the CEA on the safety of PWR reactors is presented: studies relative to the consequences of a LOCA following a rupture of the primary system, studies relative to fuel element behavior, studies on steels, reliability studies and studies of non-destructive testing methods [fr

  9. Problems related to the definition of the shielding of a large fast power reactor

    International Nuclear Information System (INIS)

    Moreau, J.

    Solutions for the shielding of a 1000 MW(e) power plant in the same technological line as Phenix are given. They have been evaluated with a monodimensional transport code. The choice is based on the comparison of their efficiency towards neutrons and on the consequences of their characteristics on the conception of the reactor tank. A few economical considerations give an idea of the influence of the choice in shielding on the cost of the power plant. At last the problem of the optimization possibilities is approached from the designer's point of view

  10. Reactor physics problems on HCPWR

    International Nuclear Information System (INIS)

    Ishiguro, Yukio; Akie, Hiroshi; Kaneko, Kunio; Sasaki, Makoto.

    1986-01-01

    Reactor physics problems on high conversion pressurized water reactors (HCPWRs) are discussed. Described in this report are outline of the HCPWR, expected accuracy for the various reactor physical qualities, and method for K-effective calculation in the resonance energy area. And requested further research problems are shown. The target value of the conversion ratio are also discussed. (author)

  11. Fast Reactor Physics. Vol. II. Proceedings of a Symposium on Fast Reactor Physics and Related Safety Problems

    International Nuclear Information System (INIS)

    1968-01-01

    Proceedings of a Symposium organized by the IAEA and held in Karlsruhe, 30 October - 3 November 1967. The meeting was attended by 183 scientists from 23 countries and three international organizations. Contents: (Vol.1) Review of national programmes (5 papers); Nuclear data for fast reactors (12 papers); Experimental methods (3 papers); Zoned systems (7 papers); Kinetics (7 papers). (Vol.11) Fast critical experiments (8 papers); Heterogeneity in fast critical experiments (5 papers); Fast power reactors (13 papers); Fast pulsed reactors (3 papers); Panel discussion. Each paper is in its original language (50 English, 11 French and 3 Russian) and is preceded by an abstract in English with a second one in the original language if this is not English. Discussions are in English. (author)

  12. Fusion reactors - types - problems

    International Nuclear Information System (INIS)

    Schmitter, K.H.

    1979-07-01

    A short account is given of the principles of fusion reactions and of the expected advantages of fusion reactors. Descriptions are presented of various Tokamak experimental devices being developed in a number of countries and of some mirror machines. The technical obstacles to be overcome before a fusion reactor could be self-supporting are discussed. (U.K.)

  13. Identification of significant problems related to light water reactor piping systems

    International Nuclear Information System (INIS)

    1980-07-01

    Work on the project was divided into three tasks. In Task 1, past surveys of LWR piping system problems and recent Licensee Event Report summaries are studied to identify the significant problems of LWR piping systems and the primary causes of these problems. Pipe cracking is identified as the most recurring problem and is mainly due to the vibration of pipes due to operating pump-pipe resonance, fluid-flow fluctuations, and vibration of pipe supports. Research relevant to the identified piping system problems is evaluated. Task 2 studies identify typical LWR piping systems and the current loads and load combinations used in the design of these systems. Definitions of loads are reviewed. In Task 3, a comparative study is carried out on the use of nonlinear analysis methods in the design of LWR piping systems. The study concludes that the current linear-elastic methods of analysis may not predict accurately the behavior of piping systems under seismic loads and may, under certain circumstances, result in nonconservative designs. Gaps at piping supports are found to have a significant effect on the response of the piping systems

  14. Study of neutronic problems related to the xenon instability in the pressurized water reactor

    International Nuclear Information System (INIS)

    Mathonniere, G.

    1988-03-01

    Xenon instabilities lead to increase initial errors. So it is extremely difficult to get an accurate calculation schema able to deal with these problems which are very important for electrical grid whose electronuclear output is large. The main task was to build a tridimensional calculation schema including nuclear, thermal hydraulic feedback. It was qualified by comparing its results with an actual experiment. Many technical problems were investigated through analytical studies or calculation results: time step, spatial mesh, finite element, convergence criterion, modelization for grids and fast control rod moves. Moreover, a 1D model, for less expensive, was studied. Its comparison with the 3D results allowed to check its accuracy and to validate the modelization of the radial laplacien and the modelization of the control rods [fr

  15. Fuel cycle problems in fusion reactors

    International Nuclear Information System (INIS)

    Hickman, R.G.

    1976-01-01

    Fuel cycle problems of fusion reactors evolve around the breeding, recovery, containment, and recycling of tritium. These processes are described, and their implications and alternatives are discussed. Technically, fuel cycle problems are solvable; economically, their feasibility is not yet known

  16. Problems of nuclear reactor safety. Vol. 1

    International Nuclear Information System (INIS)

    Shal'nov, A.V.

    1995-01-01

    Proceedings of the 9. Topical Meeting 'Problems of nuclear reactor safety' are presented. Papers include results of studies and developments associated with methods of calculation and complex computerized simulation for stationary and transient processes in nuclear power plants. Main problems of reactor safety are discussed as well as rector accidents on operating NPP's are analyzed

  17. Problems of nuclear reactor safety. Vol. 2

    International Nuclear Information System (INIS)

    Goncharov, L.A.

    1995-01-01

    Theses of proceedings of the 9 Topical Meeting on problems of nuclear power plant safety are presented. Reports include results of neutron-physical experiments carried out for reactor safety justification. Concepts of advanced reactors with improved safety are considered. Results of researches on fuel cycles are given too

  18. Political-social reactor problems at Berkeley

    International Nuclear Information System (INIS)

    Little, G.A.

    1980-01-01

    For better than ten years there was little public notice of the TRIGA reactor at UC-Berkeley. Then: a) A non-student persuaded the Student and Senate to pass a resolution to request Campus Administration to stop operation of the reactor and remove it from campus. b) Presence of the reactor became a campaign-issue in a City Mayoral election. c) Two local residents reported adverse physical reactions before, during, and after a routine tour of the reactor facility. d) The Berkeley City Council began a study of problems associated with radioactive material within the city. e) Friends Of The Earth formally petitioned the NRC to terminate the reactor's license. Campus personnel have expended many man-hours and many pounds of paper in responding to these happenings. Some of the details are of interest, and may be of use to other reactor facilities. (author)

  19. Materials problems associated with fusion reactor technology

    International Nuclear Information System (INIS)

    Dutton, R.

    This paper outlines the principles of design and operation of conceptual fusion reactors, indicates the level of research funding and activity being proposed at major centres and reviews the major materials problems which have been identified, together with an outline of the experimental techniques which have been suggested for investigating these problems. (author)

  20. Present status and problems of marine reactor

    International Nuclear Information System (INIS)

    1987-01-01

    The activities of the Research Committee on Marine Reactors are summarized, and the present status of marine reactors on the world is reviewed. The characteristics of marine reactors are discussed, and the prospect and problems of the research and development of an advanced marine reactor in Japan are reported. This Committee was established in fiscal year 1983, when the 'Mutsu' project was going to be on the right track, and the project of developing an advanced marine reactor was advanced. During four years since then, it has carried out the investigation and exchanged opinion about the activities and results of the research in foreign countries and Japan and the problems peculiar to marine reactors, that is, making small size and light weight reactors, the rolling and pitching, vibration and impact of ship hulls, the competitive power against conventional ships and so on. The idea of utilizing atomic energy for ship propulsion preceded that of electricity generation, and it was materialized in 1955 by the submarine 'Nautilus'. Now more than 300 nuclear war ships have been commissioned. Also nuclear merchant ships have been built, but the research and development were interrupted because of their economical efficiency. (Kako, I.)

  1. Tritium problems in fusion reactor systems

    International Nuclear Information System (INIS)

    Hickman, R.G.

    1975-01-01

    A brief introduction is given to the role tritium will play in the development of fusion power. The biological and worldwide environmental behavior of tritium is reviewed. The tritium problems expected in fusion power reactors are outlined. A few thoughts on tritium permeation and recent results for tritium cleanup and CT 4 accumulation are presented. Problems involving the recovery of tritium from the breeding blanket in fusion power reactors are also considered, including the possible effect of impurities in lithium blankets and the use of lithium as a regenerable getter pump. (auth)

  2. Research reactors fuel cycle problems and dilemma

    International Nuclear Information System (INIS)

    Romano, R.

    2004-01-01

    During last 10 years, some problems appeared in different steps of research reactors fuel cycle. Actually the majority of these reactors have been built in the 60s and these reactors were operated during all this long period in a cycle with steps which were dedicated to this activity. Progressively and for reasons often economical, certain steps of the cycle became more and more difficult to manage due to closing of some specialised workshops in the activities of scraps recycling, irradiated fuel reprocessing, even fuel fabrication. Other steps of the cycle meet or will meet difficulties, in particular supplying of fissile raw material LEU or HEU because this material was mostly produced in enrichment units existing mainly for military reason. Rarefaction of fissile material lead to use more and more enriched uraniums said 'of technical quality', that is to say which come from mixing of varied qualities of enriched material, containing products resulting from reprocessing. Actually, problems of end of fuel cycle are increased, either consisting of intermediary storage on the site of reactor or on specialised sites, or consisting of reprocessing. This brief summary shows most difficulties which are met today by a major part of industrials of the fuel cycle in the exercise of their activities

  3. Solving the uncommon reactor core neutronics problems

    International Nuclear Information System (INIS)

    Vondy, D.R.; Fowler, T.B.

    1980-01-01

    The common reactor core neutronics problems have fundamental neutron space, energy spectrum solutions. Typically the most positive eigenvalue is associated with an all-positive flux for the pseudo-steady-state condition (k/sub eff/), or the critical state is to be effected by selective adjustment of some variable such as the fuel concentration. With sophistication in reactor analysis has come the demand for solutions of other, uncommon neutronics problems. Importance functionss are needed for sensitivity and uncertainty analyses, as for ratios of intergral reaction rates such as the fuel conversion (breeding) ratio. The dominant higher harmonic solution is needed in stability analysis. Typically the desired neutronics solution must contain negative values to qualify as a higher harmonic or to satisfy a fixed source containing negative values. Both regular and adjoint solutions are of interest as are special integrals of the solutions to support analysis

  4. Hydrogen problems in reactor safety research

    International Nuclear Information System (INIS)

    Casper, H.

    1984-01-01

    The BMFT and BMI have initiated a workshop 'Hydrogen Problems in Reactor Safety Research' that took place October 3./4., 1983. The objective of this workshop was to present the state of the art in the main areas - Hydrogen-Production - Hydrogen-Distribution - Hydrogen-Ignition - Hydrogen-Burning and Containment Behaviour - Mitigation Measures. The lectures on the different areas are compiled. The most important results of the final discussion are summarized as well. (orig.) [de

  5. Important problems of future thermonuclear reactors*

    Directory of Open Access Journals (Sweden)

    Sadowski Marek J.

    2015-06-01

    Full Text Available This paper concerns important and difficult problems connected with a design and construction of thermonuclear reactors, which have to use nuclear fusion reactions of heavy isotopes of hydrogen, i.e., deuterium (D and tritium (T. There are described conditions in which such reactions can occur, and different methods of a high-temperature plasma generation, i.e., high-current electrical discharges, intense microwave pulses, and injection of energetic neutral atoms (NBI. There are also presented experimental facilities which can contain hot plasma for an appropriate period, and particularly so-called tokamaks. The second part presents the technical problems which must be solved in order to build a thermonuclear reactor, that might be used for energetic purposes. There are considered problems connected with a choice of constructional materials for a vacuum chamber, its internal parts, external windings generating a magnetic field, and necessary shields. The next part considers the handling of radioactive tritium; the using of alpha particles (4He for additional heating of plasma; recuperation of hydrogen isotopes absorbed in the tokamak internal parts, and a removal of a helium excess. There is presented a scheme of a future thermonuclear power plant and critical comments on a road map which should enable the construction of an industrial thermonuclear reactor (DEMO.

  6. Investigations of certain problems in reactor noise diagnostics

    International Nuclear Information System (INIS)

    Karlsson, Joakim.

    1997-06-01

    A number of problems in reactor noise diagnostics have been investigated within the framework of the present thesis. The papers presented cover three relatively different areas, namely neutron noise induced by small vibrations of a strong absorber, the decomposition of noise in BWRs with application to stability monitoring, and fluctuation analysis of soft x-ray signals from fusion plasmas. 18 refs, 6 figs

  7. Investigations of certain problems in reactor noise diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Joakim

    1997-06-01

    A number of problems in reactor noise diagnostics have been investigated within the framework of the present thesis. The papers presented cover three relatively different areas, namely neutron noise induced by small vibrations of a strong absorber, the decomposition of noise in BWRs with application to stability monitoring, and fluctuation analysis of soft x-ray signals from fusion plasmas. 18 refs, 6 figs.

  8. Corrosion problems in boiling water reactors and their remedies

    International Nuclear Information System (INIS)

    Rosborg, B.

    1989-01-01

    This article briefly presents current corrosion problems in boiling water reactors and their remedies. The problems are different forms of environmentally assisted cracking, and the remedies are divided into material-, environment-, and stress-related remedies. The list of problems comprises: intergranular stress corrosion cracking (IGSCC) in weld-sensitized stainless steel piping; IGSCC in cold-bent stainless steel piping; irradiation-assisted stress corrosion cracking (IASCC) in stainless alloys; IGSCC in high-strength stainless alloys. A prospective corrosion problem, as judged from literature references, and one which relates to plant life, is corrosion fatigue in pressure vessel steel, since the reactor pressure vessel is the most critical component in the BWR pressure boundary as regards plant safety. (author)

  9. Corrosion problems in light water nuclear reactors

    International Nuclear Information System (INIS)

    Berry, W.E.

    1984-01-01

    The corrosion problems encountered during the author's career are reviewed. Attention is given to the development of Zircaloys and attendant factors that affect corrosion; the caustic and chloride stress corrosion cracking (SCC) of austenitic stainless steel steam generator tubing; the qualification of Inconel Alloy 600 for steam generator tubing and the subsequent corrosion problem of secondary side wastage, caustic SCC, pitting, intergranular attack, denting, and primary side SCC; and SCC in weld and furnace sensitized stainless steel piping and internals in boiling water reactor primary coolants. Also mentioned are corrosion of metallic uranium alloy fuels; corrosion of aluminum and niobium candidate fuel element claddings; crevice corrosion and seizing of stainless steel journal-sleeve combinations; SCC of precipitation hardened and martensitic stainless steels; low temperature SCC of welded austenitic stainless steels by chloride, fluoride, and sulfur oxy-anions; and corrosion problems experienced by condensers

  10. The use of genetic algorithms with niching methods in nuclear reactor related problems; A utilizacao dos metodos de nichos dos algoritmos geneticos na otimizacao de problemas de reatores nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Sacco, Wagner Figueiredo

    2000-03-01

    Genetic Algorithms (GAs) are biologically motivated adaptive systems which have been used, with good results, in function optimization. However, traditional GAs rapidly push an artificial population toward convergence. That is, all individuals in the population soon become nearly identical. Niching Methods allow genetic algorithms to maintain a population of diverse individuals. GAs that incorporate these methods are capable of locating multiple, optimal solutions within a single population. The purpose of this study is to test existing niching techniques and two methods introduced herein, bearing in mind their eventual application in nuclear reactor related problems, specially the nuclear reactor core reload one, which has multiple solutions. Tests are performed using widely known test functions and their results show that the new methods are quite promising, specially in real world problems like the nuclear reactor core reload. (author)

  11. Problems and prospects of small and medium power reactors

    International Nuclear Information System (INIS)

    Matin, A.

    1977-01-01

    Prior to 1973 it was generally believed that small and medium power reactors (SMPRs) had a potentially large market and only their high capital costs prevented their large scale commercial application. In December, 1973, crude oil price rose from US $2.50 per barrel to more than US $11 per barrel. This changed the economic position of SMPRs so much so that even 100-200 MWe nuclear reactors were considered economic compared to oil-fired plants. A Market Survey by the International Atomic Energy Agency in 1974 showed that the potential market for reactors ranging from 150 to 400 MWe during 1980-1990 amounted to 140 units with a total installed capacity of 38,000 MWe. This potential market did not, however, generate the desired interest among the reactor manufacturers. So far only three manufacturers based in Europe have shown interest in SMPRs and at present small reactors are being built commercially only in India. Among developing countries, Bangladesh, Jamaica and Kuwait are seriously looking for reactors in sizes of 100-200 MWe. The paper analyses the historic background of SMPRs and problems related to their commercial application and suggests the following actions: i) The British 100 MWe SGHWR is considered proven and suitable for small grids and hence deserves financial support by British/International Financing Agencies. ii) Any re-engineered or slightly re-designed version of operating small light water reactors will find wider acceptability than available new adaptions of marine reactors. Manufacturers of operating small LWRs may be encouraged through international financial assistance to make such designs commercially available. iii) Small CANDU reactors may be suitable for most developing countries and need technical and economic support from Canada for their export. iv) The Agency must continue their effort more vigorously for making SMPRs commercially available to small developing countries

  12. Problems of space-time behaviour of nuclear reactors

    International Nuclear Information System (INIS)

    Obradovic, D.

    1966-01-01

    This paper covers a review of literature and mathematical methods applied for space-time behaviour of nuclear reactors. The review of literature is limited to unresolved problems and trends of actual research in the field of reactor physics [sr

  13. Physically - engineering problems of the Salaspils Nuclear reactor: Solutions and their topicality

    International Nuclear Information System (INIS)

    Mozgirs, Z.V.

    2005-01-01

    The paper generalizes technical solutions of physically-engineering problems of the Salaspils nuclear research reactor, experience of its modernization and exploitation. New equipment and the related technical solutions have been tested at the Salaspils reactor during its operation time and are now recommended for further use at nuclear reactors. (author)

  14. Measurement of Narora reactor building relative settlement

    International Nuclear Information System (INIS)

    Deo, P.M.; Pande, K.C.; Patwardhan, H.S.

    1977-01-01

    The civil construction of the reactor building of Narora Atomic Power Project has a special problem. The stability of the structure is liable to settlement as this location falls in seismic zone. To obviate the possibility of large scale unequal settlements, the reactor building is founded on a 4 meter thick rigid raft concreted in three layers, at a depth of 13 meters below ground. Stainless steel tanks will be embedded at 17 locations to measure relative settlements. The relative elevation difference will be detected by electrical probes when the water level in any one of the tanks touches the tip of the probes. The design envisages a maximum permissible unequal settlements of about 10 mm. over a period of 20 years. (K.B.)

  15. Engineering problems of tandem-mirror reactors

    International Nuclear Information System (INIS)

    Moir, R.W.; Barr, W.L.; Boghosian, B.M.

    1981-01-01

    We have completed a comparative evaluation of several end plug configurations for tandem mirror fusion reactors with thermal barriers. The axi-cell configuration has been selected for further study and will be the basis for a detailed conceptual design study to be carried out over the next two years. The axi-cell end plug has a simple mirror cell produced by two circular coils followed by a transition coil and a yin-yang pair, which provides for MHD stability. This paper discusses some of the many engineering problems facing the designer. We estimated the direct cost to be 2$/W/sub e/. Assuming total (direct and indirect) costs to be twice this number, we need to reduce total costs by factors between 1.7 and 2.3 to compete with future LWRs levelized cost of electricity. These reductions may be possible by designing magnets producing over 20T made possible by use of combinations of superconducting and normal conducting coils as well as improvements in performance and cost of neutral beam and microwave power systems. Scientific and technological understanding and innovation are needed in the area of thermal barrier pumping - a process by which unwanted particles are removed (pumped) from certain regions of velocity and real space in the end plug. Removal of exhaust fuel ions, fusion ash and impurities by action of a halo plasma and plasma dump in the mirror end region is another challenging engineering problem discussed in this paper

  16. Problems related with the power regulation of reactors by physico-chemical methods, and the behaviour of water and heavy water in nuclear reactors; Comportement de l'eau et de l'eau lourde dans les reacteurs nucleaires et problemes de la regulation de puissance par voie physico-chimique

    Energy Technology Data Exchange (ETDEWEB)

    Dolle, L; Conan, D; Dirian, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    The observation of the behaviour of water and heavy water in working reactors contributes to their safe running and provides information useful in studies relating to reactivity control techniques using soluble poisons. The use of nuclear poisons dissolved in the water of a reactor leads to its chemical pollution. The conditions under which they can be used without causing the undesirable effects of this pollution are studied. Problems of analysis, although important, are not tackled in this paper. Behaviour of heavy water in working reactors. Isotopic pollution of heavy water: The rate at which this pollution occurs depends on the type of reactor and on certain characteristic incidents. The use of a re-concentration column is an efficient way of maintaining the heavy water isotopic concentration in a reactor which cannot be considered exempt from slow isotopic pollution. Heavy water leak detection: The instantaneous rates of small leaks can be measured, the leak localised, and the atmospheric contamination in the reactor building checked. Isotopic analysis for deuterium or tritium determination, is carried out on samples. Chemical pollution and purification of heavy water Chemical pollution of heavy water is one of the most complex problems in reactor chemistry Corrosion of the materials which make up the core and the heavy water circuits varies extensively with the state of purity of the heavy water, as may be appreciated from the performances of the purification circuits and from direct measurements From the knowledge acquired it has been possible to work out standards of purity which, if observed will guarantee satisfactory running of the reactor. Radiolytic decomposition of heavy water : A better knowledge of its quantitative aspects in reactors is necessary in order to foresee the amounts of explosive gas mixture given off in power reactors. The radiolysis rate develops with the chemical purity of the water and the instantaneous power of the reactor

  17. Creep buckling problems in fast reactor components

    International Nuclear Information System (INIS)

    Ramesh, R.; Damodaran, S.P.; Chellapandi, P.; Chetal, S.C.; Bhoje, S.B.

    1995-01-01

    Creep buckling analyses for two important components of 500 M We Prototype Fast Breeder Reactor (PFBR), viz. Intermediate Heat Exchanger (IHX) and Inner Vessel (IV), are reported. The INCA code of CASTEM system is used for the large displacement elasto-plastic-creep analysis of IHX shell. As a first step, INCA is validated for a typical benchmark problem dealing with the creep buckling of a tube under external pressure. Prediction of INCA is also compared with the results obtained using Hoff's theory. For IV, considering the prohibitively high computational cost for the actual analysis, a simplified analysis which involves only large displacement elastoplastic buckling analysis is performed using isochronous stress strain curve approach. From both of these analysis is performed using isochronous stress strain curve approach. From both of these analysis, it has been inferred that creep buckling failure mode is not of great concern in the design of PFBR components. It has also been concluded from the analysis that Creep Cross Over Curve given in RCC-MR is applicable for creep buckling failure mode also. (author). 8 refs., 9 figs., 1 tab

  18. Localized corrosion problems in water reactors

    International Nuclear Information System (INIS)

    Coriou, Henri.

    1977-01-01

    Main localized etching on the structure materials of water reactors are studied: stress corrosion on stainless steel 304 (B.W.R), stress corrosion, 'wall thinning' and denting of Inconel 600 vapor generator tubes (P.W.R.). Some mechanisms are examined and practical exemples in reactors are described. Various possible cures are presented [fr

  19. Validation of NESTLE against static reactor benchmark problems

    International Nuclear Information System (INIS)

    Mosteller, R.D.

    1996-01-01

    The NESTLE advanced modal code was developed at North Carolina State University with support from Los Alamos National Laboratory and Idaho National Engineering Laboratory. It recently has been benchmarked successfully against measured data from pressurized water reactors (PWRs). However, NESTLE's geometric capabilities are very flexible, and it can be applied to a variety of other types of reactors. This study presents comparisons of NESTLE results with those from other codes for static benchmark problems for PWRs, boiling water reactors (BWRs), high-temperature gas-cooled reactors (HTGRs) and CANDU heavy- water reactors (HWRs)

  20. Corrosion problem in the CRENK Triga Mark II research reactor

    International Nuclear Information System (INIS)

    Kalenga, M.

    1990-01-01

    In August 1987, a routine underwater optical inspection of the aluminum tank housing the core of the CRENK Triga Mark II reactor, carried out to update safety condition of the reactor, revealed pitting corrosion attacks on the 8 mm thick aluminum tank bottom. The paper discuss the work carried out by the reactor staff to dismantle the reactor in order to allow a more precise investigation of the corrosion problem, to repair the aluminum tank bottom, and to enhance the reactor overall safety condition

  1. Validation of NESTLE against static reactor benchmark problems

    International Nuclear Information System (INIS)

    Mosteller, R.D.

    1996-01-01

    The NESTLE advanced nodal code was developed at North Carolina State University with support from Los Alamos National Laboratory and Idaho National Engineering Laboratory. It recently has been benchmarked successfully against measured data from pressurized water reactors (PWRs). However, NESTLE's geometric capabilities are very flexible, and it can be applied to a variety of other types of reactors. This study presents comparisons of NESTLE results with those from other codes for static benchmark problems for PWRs, boiling water reactors (BWRs), high-temperature gas-cooled reactors (HTGRs), and Canada deuterium uranium (CANDU) heavy-water reactors (HWRs)

  2. A Few Examples of ISPs Addressing Specific Reactor Safety Problems

    International Nuclear Information System (INIS)

    Reocreux, M.

    2008-01-01

    Four International Standard Problems which were related to safety reactor problems are briefly discussed. ISP-20 (Steam Generator Tube Rupture in DOEL 2) is a unique ISP as it is based on a real incident which occurred in a commercial Power Plant. This ISP clearly illustrated the special problems of an ISP based on a real plant, namely limited access to precise plant data, some lack in the detailed knowledge of sensor behaviour, etc. ISP-26 (ROSA IV-LSTF small break test) was an open ISP. A qualitatively good prediction of the measured events was obtained even if some modelling deficiencies were identified. ISP-27 (BETHSY Exp. 9.1 B) was a blind ISP. All important trends observed during the test were qualitatively calculated by most computer codes. However, some deficiencies in calculating some variables were evident. ISP-33 (PACTEL Natural Circulation) was an exercise with a test facility modelled on the basis of a Russian VVER 440 and with participations from Eastern and Western organisations. ISP-33 was a double-blind exercise. The simulation of some variables caused some problems although they were in principle not too complicated. Post-test calculations demonstrated significant improvements. For all the four ISPs, the influence of the code user was evident and caused some scatter in the results. A specific study was performed in ISP-26 to clarify from where those user effects were coming. The reactor safety problems related to those ISPs are detailed and the specific contribution of the ISPs to bring solutions is discussed.

  3. Vacuum problems of thermonuclear reactor design

    International Nuclear Information System (INIS)

    Paty, L.

    1981-01-01

    A thermonuclear reactor can be considered to be a vacuum system in which constant concentration should be maintained of reacting particles while permanently discharging the undesirable particles using a system of pumps. The discharging proceeds in two stages: in the former, the reactor is degassed using external pumps connected to the reactor chamber through a pumping pipe. The latter in which hydrogen is admitted, uses high pump-rate machines based on the principle of the binding of the gas to the pump surface and must not introduce molecules of higher atomic mass in the system. Turbomolecular pumps of diffusion oil pumps are most suitable for the former stage while condensation, cryosorption, titanium pumping machines and special pumping methods are most suitable for the latter stage. Examples are shown of the pump system design for Tokamak 10 and for facilities at the Euratom laboratory in Fontenay-aux-Roses. (M.D.)

  4. The problems of thermohydraulics of prospective fast reactor concepts

    International Nuclear Information System (INIS)

    Sedov, A.A.

    2000-01-01

    In this report the main requirements to fast reactors in system of future multicomponent Nuclear Power with closed U-Pu fuel cycle are regarded. The peculiarities of different liquid-metal (sodium and lead-alloyed) coolants as well as the thermohydraulics problems of prospective fast reactors (FR) concepts are discussed. (author)

  5. Nuclear data in the problem of fission reactor decommissioning

    International Nuclear Information System (INIS)

    Manokhin, V.N.; Kulagin, N.T.

    1993-01-01

    This report presents a review of the works published in Russia during last several years and devoted to the problem of nuclear data and calculations of nuclear facilities activation for fission reactor decommissioning. 6 refs

  6. Incidental transients problems in reactor. Application examples

    International Nuclear Information System (INIS)

    Marbach, G.

    1988-03-01

    The fast neutron reactor fuel element qualification should be made not only for nominal operation but also for incidental and accidental transients. Different studies and tests permit to bring this justification such as simulation in hot laboratory after irradiation of irradiated pins or specific tests interpretation [fr

  7. Nuclear graphite development, operational problems, and resolution of these problems at the Hanford production reactors

    International Nuclear Information System (INIS)

    Morgan, W.C.

    1996-01-01

    This paper chronicles the history of the Hanford Production Reactor, from the initial design considerations for B, D, and F Reactors through the selection of the agreed method for safe disposal of the decommissioned reactors. The operational problems that challenged the operations and support staff of each new generation of production reactors, the engineering actions an operational changes that alleviated or resolved the immediate problems, the changes in reactor design and design-bases for the next generation of production reactors, and the changes in manufacturing variables that resulted in new ''improved'' grades of nuclear graphites for use in the moderators of the Hanford Production Reactors are reviewed in the context of the existing knowledge-base and the mission-driven priorities on the time. 14 refs, 6 figs, 3 tabs

  8. XII seminar on problems of reactor physics

    International Nuclear Information System (INIS)

    Kryuchkov, Eh.F.; Naumov, V.I.

    2003-01-01

    Results of the XII seminar Physical problems of effective and safety use of nuclear materials taking place on the basis of MEPI (September, 2002) are discussed. Reports on the directions: physical problems of advanced nuclear-energetic technologies; account, control and nuclear material management; effective and safety use of nuclear materials at NPP; programming and software for the analysis of physical processes are performed. Of particular interest is reports on actual problems of nuclear energetics and fuel cycle, on ill-intentioned use of fissile materials, efficiency of long-lived isotopes transmutation and spent fuel management [ru

  9. Dynamic problems of power reactors and analogic devices

    International Nuclear Information System (INIS)

    Braffort, P.

    1955-01-01

    The raise of the nuclear physics came with heavy mathematical developments. The analogical installations became especially useful for precise calculations of parameters which depend the running of a reactor. They permit between other to study of kinetic problems and especially ''cybernetics'' of nuclear reactors. It doesn't make a doubt that their use will become widespread, not only in the calculations laboratories, in services for servo-mechanisms study, but also in the control panels of the reactors themselves. (M.B.) [fr

  10. Initial value problem for the equations of reactor kinetics

    International Nuclear Information System (INIS)

    Kyncl, J.

    1987-08-01

    The initial value problem for the equations of reactor kinetics is solved while taking temperature feedback into account. The space where the problem is solved is chosen such as to correspond to the mathematical properties of cross-section models. The local solution is found by the iterative method, its uniqueness is proved and it is also shown that the existence of global solution is ensured in most cases. Finally, the problem of a weak solution is discussed. (author). 5 refs

  11. Reactor physics special problem in 11. ENFIR

    International Nuclear Information System (INIS)

    Leszczynski, Francisco

    1997-01-01

    In this report, the computation method and the results of the work performed of the special topic on reactor physics proposed for the 11. ENFIR is presented. MCNP 4.2 has been adopted as the only code to perform the calculations. The full core of the IPEN-MB-1 critical unit has been modelled without important approximations. The specifications given by the Organizer Commission of the Special Topic were followed. The nuclear libraries adopted were those included on the MCNPDAT package, mainly from ENDF/B-V, except indium data, not included in this package. For indium, data obtained from LANL, based on ENDF/B-VI were used. The results are: critical position of the control banks assuming simultaneous movement: percent of extraction: (49±1)% ; excess of reactivity of the core: ρ =( 3590 ±50)pcm ; total reactivity of the one control rod bank: ρ= (4000±50) pcm. The reactivity curve of the control rods is included also. (author)

  12. On some control problems of dynamic of reactor

    Science.gov (United States)

    Baskakov, A. V.; Volkov, N. P.

    2017-12-01

    The paper analyzes controllability of the transient processes in some problems of nuclear reactor dynamics. In this case, the mathematical model of nuclear reactor dynamics is described by a system of integro-differential equations consisting of the non-stationary anisotropic multi-velocity kinetic equation of neutron transport and the balance equation of delayed neutrons. The paper defines the formulation of the linear problem on control of transient processes in nuclear reactors with application of spatially distributed actions on internal neutron sources, and the formulation of the nonlinear problems on control of transient processes with application of spatially distributed actions on the neutron absorption coefficient and the neutron scattering indicatrix. The required control actions depend on the spatial and velocity coordinates. The theorems on existence and uniqueness of these control actions are proved in the paper. To do this, the control problems mentioned above are reduced to equivalent systems of integral equations. Existence and uniqueness of the solution for this system of integral equations is proved by the method of successive approximations, which makes it possible to construct an iterative scheme for numerical analyses of transient processes in a given nuclear reactor with application of the developed mathematical model. Sufficient conditions for controllability of transient processes are also obtained. In conclusion, a connection is made between the control problems and the observation problems, which, by to the given information, allow us to reconstruct either the function of internal neutron sources, or the neutron absorption coefficient, or the neutron scattering indicatrix....

  13. Mechanical structure and problem of thorium molten salt reactor

    International Nuclear Information System (INIS)

    Kamei, Takashi

    2011-01-01

    After Fukushima Daiichi accident, there became great interest in Thorium Molten Salt Reactor (MSR) for the safety as station blackout leading to auto drainage of molten salts with freeze valve. This article described mechanical structure of MSR and problems of materials and pipes. Material corrosion problem by molten salts would be solved using modified Hastelloy N with Ti and Nb added, which should be confirmed by operation of an experimental reactor. Trends in international activities of MSR were also referred including China declaring MSR development in January 2011 to solve thorium contamination issues at rare earth production and India rich in thorium resources. (T. Tanaka)

  14. Numerical solutions to critical problem of reflected cylindrical reactor

    International Nuclear Information System (INIS)

    Horie, Junnosuke

    1977-01-01

    The multi-region critical problem can be transformed into an eigenvalue problem in the classical sense by using the method of Kuscer and Corngold and of Wing. This transformation is applied to derive a variational formulation for a reflected reactor. An approximate critical value of the multiplying factor is determined by maximizing the Rayleigh quotient for radially and totally reflected cylindrical reactors. It is shown that this approximate critical value is an upper bound of the true critical value. From the facts that the operator is self-adjoint and the eigenfunction is positive, an expression is derived for the upper and lower bounds of the true eigenvalue, by making use of the approximate distribution. The difference of the upper and lower bounds is an uncertainty of the presumption of the true critical value. It is found that we can compute the bounds to any required precision. The narrow bounds are calculated for two radially and one totally reflected cylindrical reactors. (auth.)

  15. AIREK-PUL, Periodic Kinetics Problems of Pulsed Reactors

    International Nuclear Information System (INIS)

    Inzaghi, A.; Misenta, R.

    1984-01-01

    1 - Nature of physical problem solved: Solves periodic problems about the kinetics of pulsed reactors or problems where the reactivity has rapid variations. The program uses two constant steps for the integration of the system of differential equations, the first step during the first half-period and the second step during the second half-period. Available for either single or double precision. 2 - Method of solution: The differential equations are integrated using the fourth-order Runge-Kutta method as modified by E.R. Cohen (Geneva Conference, 1958). 3 - Restrictions on the complexity of the problem: The maximum number of differential equations that can be solved simultaneously is 50

  16. Some particular problems put by operating experimental reactors

    International Nuclear Information System (INIS)

    Candiotti, C.; Mabeix, R.; Uguen, R.

    1960-01-01

    On basis of a six years experience in operating research reactors, the authors explain, first, the difference in their utilization between these piles and another similar ones and, after, in consequence, they set off corresponding servitudes. These servitudes put very particular problems in operating itself, maintenance, modifications or additions on these apparatus. (author) [fr

  17. Solving the uncommon nuclear reactor core neutronics problems

    International Nuclear Information System (INIS)

    Vondy, D.R.; Fowler, T.B.

    1983-01-01

    Calculational procedures have been implemented for solving importance and higher harmonic neutronics problems. Solutions are obtained routinely to support analysis of reactor core performance, treating up to three space coordinates with the multigroup diffusion theory approximation to neutron transport. The techniques used and some of the calculational difficulties are discussed

  18. Metallic materials corrosion problems in molten salt reactors

    International Nuclear Information System (INIS)

    Chauvin, G.; Dixmier, J.; Jarny, P.

    1977-01-01

    The USA forecastings concerning the molten salt reactors are reviewed (mixtures of fluorides containing the fuel, operating between 560 and 700 0 C). Corrosion problems are important in these reactors. The effects of certain characteristic factors on corrosion are analyzed: humidity and metallic impurities in the salts, temperature gradients, speed of circulation of salts, tellurium from fission products, coupling. In the molten fluorides and experimental conditions, the materials with high Ni content are particularly corrosion resistant alloys (hastelloy N). The corrosion of this material is about 2.6 mg.cm -2 at 700 0 C [fr

  19. Improvements in or relating to nuclear reactors

    International Nuclear Information System (INIS)

    Timofeev, A.V.; Batjukov, V.I.; Fadeev, A.I.; Shapkin, A.F.; Shikhiyan, T.G.; Ordynsky, G.V.; Drachev, V.P.; Pogodin, E.N.

    1980-01-01

    A refuelling installation for nuclear reactor complexes is described for recharging the reactor vessels of such complexes with new fuel assemblies and for removing spent fuel assemblies from the reactor vessel. (U.K.)

  20. Present status and problems of development of fast breeder reactors

    International Nuclear Information System (INIS)

    Ikeda, Hiroshi

    1984-11-01

    The development of FBRs in Japan now reached the stage to conclude on the development organization for a demonstration reactor positioning one step before a practical reactor. FBRs can be operated while converting uranium-238 existing in natural uranium by 99.3% to fissile plutonium-239, as the result, the nuclear fuel more than that consumed can be produced. However, there are various technical difficulties in FBRs, and the construction cost is estimated to be considerably higher as compared with that of LWRs. Also the plutonium obtained by reprocessing spent fuel is used for FBRs, accordingly, the development of FBRs is inseparable from the establishment of nuclear fuel cycle. In order to get rid of the burden of enormous development cost for FBRs, the trend of international joint development is conspicuous. The Superphenix with 1200 MWe output under construction centering around SERENA is expected to attain the criticality in the spring of 1985. For the development of a demonstration reactor, it is necessary to increase the role of private businesses, and the smooth transfer of know-how accumulated in Power Reactor and Nuclear Fuel Development Corp. to civilian side is an important problem. (Kako, I.)

  1. Constitutive relations for nuclear reactor core materials

    International Nuclear Information System (INIS)

    Zaverl, F. Jr.; Lee, D.

    1978-01-01

    A strain rate dependent constitutive equation is proposed which is capable of describing inelastic deformation behavior of anisotropic metals, such as Zircaloys, under complex loading conditions. The salient features of the constitutive equations are that they describe history dependent inelastic deformation behaviour of anisotropic metals under three-dimensional stress states in the presence of fast neutron flux. It is shown that the general form of the constitutive relations is consistent with experimental observations made under both unirradiated and irradiated conditions. The utility of the model is demonstrated by examining the analytical results obtained for a segment of tubing undergoing different loading histories in a reactor. (Auth.)

  2. Genetic algorithm with fuzzy clustering for optimization of nuclear reactor problems

    International Nuclear Information System (INIS)

    Machado, Marcelo Dornellas; Sacco, Wagner Figueiredo; Schirru, Roberto

    2000-01-01

    Genetic Algorithms (GAs) are biologically motivated adaptive systems which have been used, with good results, in function optimization. However, traditional GAs rapidly push an artificial population toward convergence. That is, all individuals in the population soon become nearly identical. Niching Methods allow genetic algorithms to maintain a population of diverse individuals. GAs that incorporate these methods are capable of locating multiple, optimal solutions within a single population. The purpose of this study is to introduce a new niching technique based on the fuzzy clustering method FCM, bearing in mind its eventual application in nuclear reactor related problems, specially the nuclear reactor core reload one, which has multiple solutions. tests are performed using widely known test functions and their results show that the new method is quite promising, specially to a future application in real world problems like the nuclear reactor core reload. (author)

  3. Utilization of niching methods of genetic algorithms in nuclear reactor problems optimization

    International Nuclear Information System (INIS)

    Sacco, Wagner Figueiredo; Schirru, Roberto

    2000-01-01

    Genetic Algorithms (GAs) are biologically motivated adaptive systems which have been used, with good results, in function optimization. However, traditional GAs rapidly push an artificial population toward convergence. That is, all individuals in the population soon become nearly identical. Niching Methods allow genetic algorithms to maintain a population of diverse individuals. GAs that incorporate these methods are capable of locating multiple, optimal solutions within a single population. The purpose of this study is to test existing niching techniques and two methods introduced herein, bearing in mind their eventual application in nuclear reactor related problems, specially the nuclear reactor core reload one, which has multiple solutions. Tests are performed using widely known test functions and their results show that the new methods are quite promising, specially in real world problems like the nuclear reactor core reload. (author)

  4. The assessment of structural dynamics problems in nuclear reactor safety

    International Nuclear Information System (INIS)

    Liebe, R.

    1978-10-01

    The paper discusses important physical features of structural dynamics problems in reactor safety. First a general characterization is given of the following problems: Containment deformation due to pool-dynamics during BWR-blowdown; behavior of the core internals due to PWR-blowdown loads; dynamic response of a nuclear power plant during an earthquake; fuel element deformation due to local pressure pulses in an LMFBR core. Several criterias are formulated to classify typical problems so that a better choise can be made both of appropriate mathematical/numerical as well as experimental techniques. The degree of physical coupling between structural dynamics and fluid dynamics is discussed in more detail since it requires particular attention when selecting problem-oriented methods of solution. Some examples are given to illustrate the application and to compare advantages and disadvantages of several numerical methods. Then description is given of experimental techniques in structural dynamics and typical problem areas are identified. Finally some results are presented concerning the fuel element deformation problem in LMFBRs and from the general considerations some important conclusions are summarized. (orig.) 891 RW 892 AP [de

  5. Fast reactors and problems in their development. Chapter 6

    International Nuclear Information System (INIS)

    Dombey, N.

    1980-01-01

    The main differences between fast reactors, in particular the liquid-metal fast breeder reactor (LMFBR), and thermal reactors are discussed. The view is taken, based on the intrinsic physics of the systems, that fast reactors should be considered as a different genus from thermal reactors. Some conclusions are drawn for fast reactor development generally and for the British programme in particular. Physics, economics and safety aspects are covered. (U.K.)

  6. Assessment of Power Quality Problems for TRIGA PUSPATI Reactor (RTP)

    International Nuclear Information System (INIS)

    Mohd Fazli Zakaria; Ramachandaramurthy, V.K.

    2016-01-01

    The electrical power systems are exposed to different types of power quality disturbances. Investigation and monitoring of power quality is necessary to maintain accurate operation of sensitive equipment especially for nuclear installations. This paper will discuss the power quality problems observed at the electrical sources of PUSPATI TRIGA Reactor (RTP). Assessment of power quality requires the identification of any anomalous behavior on a power system, which adversely affects the normal operation of electrical or electronic equipment. A power quality assessment involves gathering data resources; analyzing the data (with reference to power quality standards) then, if problems exist, recommendation of mitigation techniques must be considered. Field power quality data is collected by power quality recorder and analyzed with reference to power quality standards. Normally the electrical power is supplied to the RTP via two sources in order to keep a good reliability where each of them is designed to carry the full load. The assessment of power quality during reactor operation was performed for both electrical sources. There were several disturbances such as voltage harmonics and flicker that exceeded the thresholds. (author)

  7. Material problems in accident analysis of prestressed concrete reactor vessels

    International Nuclear Information System (INIS)

    Bazant, Z.P.

    1977-01-01

    Due to their very high energy absorption capability, as well as their inherent safety advantages, prestressed concrete reactor vessels are presently being keenly studied as the basic barrier to contain hypothetical core disruptive accidents in a fast breeder reactor. One problem investigated is the nonlinear constitutive behavior and failure criteria for concrete. Previously, a comprehensive theory, called endochronic theory, has been shown to satisfy all basic currently known features of test data. Nevertheless uncertainty still exists with regard to non-proportional loading paths, for which good test data are lacking at present. An extension of the endochronic theory which correlates best with general experimental evidence and includes fracturing terms is given, and a comparison with vertex-type hardening in plasticity is made. A second problem which must be analysed in accident situations is the high temperature shock on the concrete walls (due to liquid sodium, up to 850 0 C). Refining a previous crude formulation, a rational model for calculating moisture and heat transfer and pore pressures in concrete subjected to thermal shock is presented. In conclusion, a new design concept, in which the concrete vessel is completely dehydrated and kept hot throughout its service life in order to substantially improve its response to thermal shock as well as liquid sodium contact, is described. (Auth.)

  8. Application of the HGPT methodology of reactor operation problems with a nodal mixed method

    International Nuclear Information System (INIS)

    Baudron, A.M.; Bruna, G.B.; Gandini, A.; Lautard, J.J.; Monti, S.; Pizzigati, G.

    1998-01-01

    The heuristically based generalized perturbation theory (HGPT), to first and higher order, applied to the neutron field of a reactor system, is discussed in relation to quasistatic problems. This methodology is of particular interest in reactor operation. In this application it may allow an on-line appraisal of the main physical responses of the reactor system when subject to alterations relevant to normal system exploitation, e.g. control rod movement, and/or soluble boron concentration changes to be introduced, for instance, for compensating power level variations following electrical network demands. In this paper, after describing the main features of the theory, its implementation into the diffusion, 3D mixed dual nodal code MINOS of the SAPHYR system is presented. The results from a small scale investigation performed on a simplified PWR system corroborate the validity of the methodology proposed

  9. A modified firefly algorithm applied to the nuclear reload problem of a pressurized water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Iona Maghali Santos de; Schirru, Roberto, E-mail: ioliveira@con.ufrj.b, E-mail: schirru@lmp.ufrj.b [Universidade Federal do Rio de Janeiro (PEN/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Programa de Engenharia Nuclear

    2011-07-01

    The Nuclear Reactor Reload Problem (NRRP) is an issue of great importance and concern in nuclear engineering. It is the problem related with the periodic operation of replacing part of the fuel of a nuclear reactor. Traditionally, this procedure occurs after a period of operation called a cycle, or whenever the nuclear power plant is unable to continue operating at its nominal power. Studied for more than 40 years, the NRRP still remains a challenge for many optimization techniques due to its multiple objectives concerning economics, safety and reactor physics calculations. Characteristics such as non-linearity, multimodality and high dimensionality also make the NRRP a very complex optimization problem. In broad terms, it aims at getting the best arrangement of fuel in the nuclear reactor core that leads to a maximization of the operating time. The primary goal is to design fuel loading patterns (LPs) so that the core produces the required energy output in an economical way, without violating safety limits. Since multiple feasible solutions can be obtained to this problem, judicious optimization is required in order to identify the most economical among them. In this sense, this paper presents a new contribution in this area and introduces a modified firefly algorithm (FA) to perform LPs optimization for a pressurized water reactor. Based on the original FA introduced by Xin-She Yang in 2008, the proposed methodology seems to be very promising as an optimizer to the NRRP. The experiments performed and the comparisons with some well known best performing algorithms from the literature, confirm this statement. (author)

  10. A modified firefly algorithm applied to the nuclear reload problem of a pressurized water reactor

    International Nuclear Information System (INIS)

    Oliveira, Iona Maghali Santos de; Schirru, Roberto

    2011-01-01

    The Nuclear Reactor Reload Problem (NRRP) is an issue of great importance and concern in nuclear engineering. It is the problem related with the periodic operation of replacing part of the fuel of a nuclear reactor. Traditionally, this procedure occurs after a period of operation called a cycle, or whenever the nuclear power plant is unable to continue operating at its nominal power. Studied for more than 40 years, the NRRP still remains a challenge for many optimization techniques due to its multiple objectives concerning economics, safety and reactor physics calculations. Characteristics such as non-linearity, multimodality and high dimensionality also make the NRRP a very complex optimization problem. In broad terms, it aims at getting the best arrangement of fuel in the nuclear reactor core that leads to a maximization of the operating time. The primary goal is to design fuel loading patterns (LPs) so that the core produces the required energy output in an economical way, without violating safety limits. Since multiple feasible solutions can be obtained to this problem, judicious optimization is required in order to identify the most economical among them. In this sense, this paper presents a new contribution in this area and introduces a modified firefly algorithm (FA) to perform LPs optimization for a pressurized water reactor. Based on the original FA introduced by Xin-She Yang in 2008, the proposed methodology seems to be very promising as an optimizer to the NRRP. The experiments performed and the comparisons with some well known best performing algorithms from the literature, confirm this statement. (author)

  11. Sensitivity and Uncertainty Analysis of Coupled Reactor Physics Problems : Method Development for Multi-Physics in Reactors

    NARCIS (Netherlands)

    Perkó, Z.

    2015-01-01

    This thesis presents novel adjoint and spectral methods for the sensitivity and uncertainty (S&U) analysis of multi-physics problems encountered in the field of reactor physics. The first part focuses on the steady state of reactors and extends the adjoint sensitivity analysis methods well

  12. A top priority problem of national radiation protection - proper disposal of research reactor spent fuel

    International Nuclear Information System (INIS)

    Marinkovic, N.; Matausek, M.V.; Jovic, V.

    1997-01-01

    The paper presents basic facts about RA research reactor at the Vinca Institute. The present state of the RA reactor spent fuel storage pool appears to be a serious safety and radiological problem, which must be solved urgently, independent of the decision about the future status of the reactor itself. The following paragraphs describe current activities on improving storage conditions of the research reactor RA spent fuel. Activities performed so far, concerning identification and improvement of the spent fuel storage conditions are presented. These are verification of radiation protection measures, radiological and chemical analyses, visual inspection and photographing, safety analyses and nuclear criticality studies.A project for long-term solution of the research reactor spent fuel storage is proposed. In order to minimise further corrosion and establish strict control of all the relevant technological parameters of the utility, improvement of conditions for disposal of the fuel in the existing storage, is foreseen in the first phase. New dry storage for long-term storing of the spent fuel should be built during the second phase of the project. Particular attention is paid to the activities related to radiation protection and waste treatment, starting from standard monitoring and control, radiological analyses, regulations and legislation, to complicated handling of high level radioactive waste. (authors)

  13. Depletion GPT-free sensitivity analysis for reactor eigenvalue problems

    International Nuclear Information System (INIS)

    Kennedy, C.; Abdel-Khalik, H.

    2013-01-01

    This manuscript introduces a novel approach to solving depletion perturbation theory problems without the need to set up or solve the generalized perturbation theory (GPT) equations. The approach, hereinafter denoted generalized perturbation theory free (GPT-Free), constructs a reduced order model (ROM) using methods based in perturbation theory and computes response sensitivity profiles in a manner that is independent of the number or type of responses, allowing for an efficient computation of sensitivities when many responses are required. Moreover, the reduction error from using the ROM is quantified in the GPT-Free approach by means of a Wilks' order statistics error metric denoted the K-metric. Traditional GPT has been recognized as the most computationally efficient approach for performing sensitivity analyses of models with many input parameters, e.g. when forward sensitivity analyses are computationally intractable. However, most neutronics codes that can solve the fundamental (homogenous) adjoint eigenvalue problem do not have GPT capabilities unless envisioned during code development. The GPT-Free approach addresses this limitation by requiring only the ability to compute the fundamental adjoint. This manuscript demonstrates the GPT-Free approach for depletion reactor calculations performed in SCALE6 using the 7x7 UAM assembly model. A ROM is developed for the assembly over a time horizon of 990 days. The approach both calculates the reduction error over the lifetime of the simulation using the K-metric and benchmarks the obtained sensitivities using sample calculations. (authors)

  14. Sodium coolant of fast reactors: Experience and problems

    International Nuclear Information System (INIS)

    Kozlov, F.A.; Volchkov, L.G.; Drobyshev, A.V.; Nikulin, M.P.; Kochetkov, L.A.; Alexeev, V.V.

    1997-01-01

    In present report the following subjects are considered: state of the coolant and sodium systems under normal operating condition as well as under decommissioning, disclosing of sodium circuits and liquidation of its consequences, cleaning from sodium and decontamination under repairing works of equipment and circuits. Cleaning of coolant and sodium systems under normal operating conditions and under accident contamination. Cleaning of the equipment under repairing works and during decommissioning from sodium and products of its interaction with water and air. Treatment of sodium waste, taking into account a possibility of sodium fires. It is shown that the state of coolant, cover gas, surfaces of constructive materials which are in contact with them, cleaning systems, formed during installation operation require development of specific technologies. Developed technologies ensured safety operation of sodium cooled installations as in normal operating conditions so in abnormal situations. R and D activities in this field and experience gained provided a solid base for coping with problems arising during decommissioning. Prospective research problems are emphasized where the future efforts should be concentrated in order to improve characteristics of sodium cooled reactors and to make their decommissioning optimal and safe. (author)

  15. Argentinean activities related to Fast Reactors

    International Nuclear Information System (INIS)

    Azpitarte, Osvaldo

    2012-01-01

    CNEA objectives in the area of Generation IV nuclear reactors: Implement a programme for the monitoring of the global progress of new technologies for Generation IV nuclear reactors and their fuel cycles, in order to generate and assess associated lines of R&D. – Perform studies and evaluations for defining the Generation IV line or lines on which CNEA would be interested; – Promote the participation on specific international projects; – Implementation of experimental facilities

  16. Traction-related problems after hip arthroscopy

    DEFF Research Database (Denmark)

    Frandsen, Lone; Lund, Bent; Grønbech Nielsen, Torsten

    2017-01-01

    . The questionnaire included questions on patients' perceptions of traction-related problems in the groin area, at the knee and ankle and how patients had coped with these problems. A total of 100 consecutive patients undergoing hip arthroscopy filled out the questionnaire. Primary findings of this study were that 74......% of patients reported some sort of traction-related problems after hip arthroscopy. About 32% of the patients had problems in the groin area and 49% of the patients complained of symptoms in the knee joint. A total of 37% of the patients had experienced problems from the traction boot in the ankle area....... The complications were found to be temporary and disappeared after 2-4 weeks. Five patients still had complaints after 3 months. All five patients had a pre-existing knee injury prior to undergoing hip arthroscopy. Traction-related problems after hip arthroscopy are a challenge and our study showed that 74...

  17. Traction-related problems after hip arthroscopy

    Science.gov (United States)

    Lund, Bent; Grønbech Nielsen, Torsten; Lind, Martin

    2017-01-01

    Abstract Traction-related problems are poorly described in the existing literature. The purpose of this prospective study was to describe traction-related problems and how patients perceive these problems. The study was a descriptive cohort study and data were collected from questionnaires and patient files. The questionnaire included questions on patients’ perceptions of traction-related problems in the groin area, at the knee and ankle and how patients had coped with these problems. A total of 100 consecutive patients undergoing hip arthroscopy filled out the questionnaire. Primary findings of this study were that 74% of patients reported some sort of traction-related problems after hip arthroscopy. About 32% of the patients had problems in the groin area and 49% of the patients complained of symptoms in the knee joint. A total of 37% of the patients had experienced problems from the traction boot in the ankle area. The complications were found to be temporary and disappeared after 2–4 weeks. Five patients still had complaints after 3 months. All five patients had a pre-existing knee injury prior to undergoing hip arthroscopy. Traction-related problems after hip arthroscopy are a challenge and our study showed that 74% of the patients reported traction-related problems. This is significantly higher than previously reported. The present study found a high rate of complaints from the knee and ankle joints that have not previously been reported. The presented data suggest the need for more pre-surgery patient information about possible traction-related problems. PMID:28630721

  18. Study of different fitness functions with safety restriction for nuclear reactor reload problem using QDPSO

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Paulo C. de, E-mail: paulocaixeta@poli.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Departamento de Engenharia Nuclear; Lima, Alan M.M. de; Schirru, Roberto, E-mail: alan@lmp.ufrj.br, E-mail: schirru@lmp.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Nuclear Reactor Reload Problem (NRRP) is a classical problem in Nuclear Engineering that has been studied for more than 40 years, which focuses on the economics and safety of the Nuclear Power Plant (NPP). This problem consists in searching for the best loading pattern of fuel assemblies (FA) in the core, aiming to determine the permutation of fuel assemblies that optimizes the uranium utilization, with fitness function evaluated according to specific criteria and methods of nuclear reactor physics, such as the maximum mean power peak and the boron concentration. In this article will be presented different methodologies to obtain a representative fitness function for NRRP, where Quantum particle Swarm optimization (QPSO) was used to determine which one gives the best array of fuel assemblies that will make the maximum EFPD (Effective Full Power Days) with the least computational effort. In this approach, as well as others in literature, was not used Burnable Poison in the simulations and the results will be compared in relation of the maximization of the cycle length considering the boron concentration yield by the reactor physics code, to make sure that the configuration is valid from a safety point of view. This paper was based on Angra 1's seventh reload cycle. (author)

  19. The gravitational attraction algorithm: a new metaheuristic applied to a nuclear reactor core design optimization problem

    International Nuclear Information System (INIS)

    Sacco, Wagner F.; Oliveira, Cassiano R.E. de

    2005-01-01

    A new metaheuristic called 'Gravitational Attraction Algorithm' (GAA) is introduced in this article. It is an analogy with the gravitational force field, where a body attracts another proportionally to both masses and inversely to their distances. The GAA is a populational algorithm where, first of all, the solutions are clustered using the Fuzzy Clustering Means (FCM) algorithm. Following that, the gravitational forces of the individuals in relation to each cluster are evaluated and this individual or solution is displaced to the cluster with the greatest attractive force. Once it is inside this cluster, the solution receives small stochastic variations, performing a local exploration. Then the solutions are crossed over and the process starts all over again. The parameters required by the GAA are the 'diversity factor', which is used to create a random diversity in a fashion similar to genetic algorithm's mutation, and the number of clusters for the FCM. GAA is applied to the reactor core design optimization problem which consists in adjusting several reactor cell parameters in order to minimize the average peak-factor in a 3-enrichment-zone reactor, considering operational restrictions. This problem was previously attacked using the canonical genetic algorithm (GA) and a Niching Genetic Algorithm (NGA). The new metaheuristic is then compared to those two algorithms. The three algorithms are submitted to the same computational effort and GAA reaches the best results, showing its potential for other applications in the nuclear engineering field as, for instance, the nuclear core reload optimization problem. (author)

  20. Self-teaching neural network learns difficult reactor control problem

    International Nuclear Information System (INIS)

    Jouse, W.C.

    1989-01-01

    A self-teaching neural network used as an adaptive controller quickly learns to control an unstable reactor configuration. The network models the behavior of a human operator. It is trained by allowing it to operate the reactivity control impulsively. It is punished whenever either the power or fuel temperature stray outside technical limits. Using a simple paradigm, the network constructs an internal representation of the punishment and of the reactor system. The reactor is constrained to small power orbits

  1. Closing nuclear fuel cycle with fast reactors: problems and prospects

    Energy Technology Data Exchange (ETDEWEB)

    Shadrin, A.; Dvoeglazov, K.; Ivanov, V. [Bochvar Institute - VNIINM, Moscow (Russian Federation)

    2013-07-01

    The closed nuclear fuel cycle (CNFC) with fast reactors (FR) is the most promising way of nuclear energetics development because it prevents spent nuclear fuel (SNF) accumulation and minimizes radwaste volume due to minor actinides (MA) transmutation. CNFC with FR requires the elaboration of safety, environmentally acceptable and economically effective methods of treatment of SNF with high burn-up and low cooling time. The up-to-date industrially implemented SNF reprocessing technologies based on hydrometallurgical methods are not suitable for the reprocessing of SNF with high burn-up and low cooling time. The alternative dry methods (such as electrorefining in molten salts or fluoride technologies) applicable for such SNF reprocessing have not found implementation at industrial scale. So the cost of SNF reprocessing by means of dry technologies can hardly be estimated. Another problem of dry technologies is the recovery of fissionable materials pure enough for dense fuel fabrication. A combination of technical solutions performed with hydrometallurgical and dry technologies (pyro-technology) is proposed and it appears to be a promising way for the elaboration of economically, ecologically and socially accepted technology of FR SNF management. This paper deals with discussion of main principle of dry and aqueous operations combination that probably would provide safety and economic efficiency of the FR SNF reprocessing. (authors)

  2. EARTH RESOURCE PROBLEMS AND RELATED ENVIRONMENTAL CONSIDERATIONS

    Directory of Open Access Journals (Sweden)

    Orlitová Erika

    1997-10-01

    Full Text Available The paper discusses some of the problems of geology and earth resources management in relation to environmental problems of the technosphere. It deals also with some aspects of environmental monitoring of areas where surveying or mining operations are planned or in progress.

  3. Depression and Related Problems in University Students

    Science.gov (United States)

    Field, Tiffany; Diego, Miguel; Pelaez, Martha; Deeds, Osvelia; Delgado, Jeannette

    2012-01-01

    Method: Depression and related problems were studied in a sample of 283 university students. Results: The students with high depression scores also had high scores on anxiety, intrusive thoughts, controlling intrusive thoughts and sleep disturbances scales. A stepwise regression suggested that those problems contributed to a significant proportion…

  4. Problems of nuclear reactor safety. Vol. 1; Problemy bezopasnosti yaderno-ehnergeticheskikh ustanovok. Tom 1

    Energy Technology Data Exchange (ETDEWEB)

    Shal` nov, A V [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation)

    1996-12-31

    Proceedings of the 9. Topical Meeting `Problems of nuclear reactor safety` are presented. Papers include results of studies and developments associated with methods of calculation and complex computerized simulation for stationary and transient processes in nuclear power plants. Main problems of reactor safety are discussed as well as rector accidents on operating NPP`s are analyzed.

  5. Improvements in or relating to nuclear reactors

    International Nuclear Information System (INIS)

    Savin, N.I.; Khramov, D.A.; Filippov, V.J.; Bugrov, V.V.

    1979-01-01

    A nuclear reactor is described, comprising a core accommodating a plurality of fuel assemblies and a refuelling device for replacing spent fuel assemblies. The design of the fuel assembly and of the refuelling device, and the method of carrying out the refuelling operation, are specified. (U.K.)

  6. Contribution to the study of thermal-hydraulic problems in nuclear reactors

    International Nuclear Information System (INIS)

    Cognet, G.

    1998-01-01

    In nuclear reactors, whatever the type considered, Pressurized Water Water Reactors (PWRs), Fast Breeder reactors (FBRs)..., thermal-hydraulics, the science of fluid mechanics and thermal behaviour, plays an essential role, both in nominal operating and accidental conditions. Fluid can either be the primary fluid (liquid or gas) or a very specific fluid called corium, which, in case of severe accident, could result from core and environning structure melting. The work reported here represents a 20-year contribution to thermal-hydraulic issues which could occur in FBRs and PWRs. Working on these two types of reactors, both in nominal and severe accident situations, has allowed me to compare the problems and to realize the importance of communication between research teams. The evolution in the complexity of studied problems, unavoidable in order to reduce costs and significantly improve safety, has led me from numerical modelling of single-phase flow turbulence to high temperature real melt experiments. The difficulties encountered in understanding the observed phenomena and in increasing experimental databases for computer code qualification have often entailed my participation in specific measurement device developments or adaptations, in particular non-intrusive devices generally based on optical techniques. Being concerned about the end-use of this research work, I actively participated in 'in-situ' thermalhydraulic experiments in the FBRs: Phenix and Super-Phenix, of which I appreciated their undeniable scientific contribution. In my opinion, the thermal-hydraulic questions related to severe accidents are the most complex as they are at the cross-roads of several scientific specialities. Consequently, they require a multi-disciplinary approach and a continuous see-saw motion between experimentalists and modelling teams. After a brief description of the various problems encountered, the main ones are reported. Finally, the importance for research teams to

  7. Nintendo related injuries and other problems: review.

    Science.gov (United States)

    Jalink, Maarten B; Heineman, Erik; Pierie, Jean-Pierre E N; ten Cate Hoedemaker, Henk O

    2014-12-16

    To identify all reported cases of injury and other problems caused by using a Nintendo video gaming system. Review. Search of PubMed and Embase in June 2014 for reports on injuries and other problems caused by using a Nintendo gaming system. Most of the 38 articles identified were case reports or case series. Injuries and problems ranged from neurological and psychological to surgical. Traditional controllers with buttons were associated with tendinitis of the extensor of the thumb. The joystick on the Nintendo 64 controller was linked to palmar ulceration. The motion sensitive Wii remote was associated with musculoskeletal problems and various traumas. Most problems are mild and prevalence is low. The described injuries were related to the way the games are controlled, which varies according to the video game console. © Jalink et al 2014.

  8. Problems and prospects of small and medium power reactors

    International Nuclear Information System (INIS)

    Matin, A.

    1977-01-01

    Prior to 1973 it was generally believed that small and medium power reactors (SMPRs) had a potentially large market and only their high capital costs prevented their large-scale commercial application. The increase in the price of crude oil in December 1973 changed the economic position of SMPRs so much that even 100-200MW(e) nuclear reactors were considered economic compared with oil-fired plants. The IAEA 1974 market survey showed a potential for 154 units from 150-500MW(e) during 1980-1989 with a total installed capacity of 45000MW(e). This did not generate the desired interest among reactor manufacturers. So far only three European-based manufacturers have shown interest in SMPRs and at present small reactors are being built commercially mostly in India. The reported capital costs of a 215MW(e) Indian CANDU reactor compare favourably with those for European-built reactors. Bangladesh, Jamaica and Kuwait are seriously looking for reactors of 50-150MW(e). The paper analyses the historical background of SMPRs and their commercial application and suggests the following action: (1) A realistic reappraisal of the changed market potential for SMPRs and a critical analysis of the Indian and European figures, possibly carried out by the IAEA; (2) a Special Nuclear Fund be created by contributions from Member States to provide financial support to selected reactor manufacturers willing to make SMPRs commercially available; (3) the proposed Special Nuclear Fund may also provide credit on soft terms to developing countries interested in building SMPRs; (4) the IAEA should expand the scope of its activities and take up the responsibility of collecting and administering such a Special Nuclear Fund. (author)

  9. Research activity on thermohydraulic problems of PWR reactors

    International Nuclear Information System (INIS)

    Szabados, L.

    1976-06-01

    The general review of the experimental and theoretical research works on thermohydraulic investigation of pressurized water type reactors being done in the Central Research Institute for Physics is given. The main results of the theoretical and theoretical-numerical research are summarized. The most important result of the past years is the construction of the High Pressure Water Cooled Loop (NVH) thermohydraulic loop. Another significant achievement was the development of the reactor thermohydraulic program system. (Sz.N.Z.)

  10. The Burnside problem and related topics

    International Nuclear Information System (INIS)

    Adian, Sergei I

    2011-01-01

    This paper gives a survey of results related to the famous Burnside problem on periodic groups. A negative solution of this problem was first published in joint papers of P.S. Novikov and the author in 1968. The theory of transformations of words in free periodic groups that was created in these papers and its various modifications give a very productive approach to the investigation of hard problems in group theory. In 1950 the Burnside problem gave rise to another problem on finite periodic groups, formulated by Magnus and called by him the restricted Burnside problem. Here it is called the Burnside-Magnus problem. In the Burnside problem the question of local finiteness of periodic groups of a given exponent was posed, but the Burnside-Magnus problem is the question of the existence of a maximal finite periodic group R(m,n) of a fixed period n with a given number m of generators. These problems complement each other. The publication in a joint paper by the author and Razborov in 1987 of the first effective proof of the well-known result of Kostrikin on the existence of a maximal group R(m,n) for any prime n, together with an indication of primitive recursive upper bounds for the orders of these groups, stimulated investigations of the Burnside-Magnus problem as well. Very soon other effective proofs appeared, and then Zel'manov extended Kostrikin's result to the case when n is any power of a prime number. These results are discussed in the last section of this paper. Bibliography: 105 titles.

  11. Problems of control of WWER-type pressurized water reactors (PWR's)

    International Nuclear Information System (INIS)

    Drab, F.; Grof, V.

    1978-01-01

    The problems are dealt with of nuclear power reactor control. Special attention is paid to the reactor of the WWER type, which will play the most important part in the Czechoslovak power system in the near future. The subsystems are described which comprise the systems of reactor control and protection. The possibilities are outlined of using Czechoslovak instrumentation for the control and safety system of the WWER-type PWR. (author)

  12. Basic researches on thermo-hydraulic non-equilibrium phenomena related to nuclear reactor safety

    International Nuclear Information System (INIS)

    Sakurai, Akira; Kataoka, Isao; Aritomi, Masanori.

    1989-01-01

    A review was made of recent developments of fundamental researches on thermo-hydraulic non-equilibrium phenomena related to light water reactor safety, in relation to problems to be solved for the improvement of safety analysis codes. As for the problems related to flow con ditions, fundamental researches on basic conservation equations and constitutive equations for transient two-phase flow were reviewed. Regarding to the problems related to thermal non-equilibrium phenomena, fundamental researches on film boiling in pool and forced convection, transient boiling heat transfer and flow behavior caused by pressure transients were reviewed. (author)

  13. Coarse-grained parallel genetic algorithm applied to a nuclear reactor core design optimization problem

    International Nuclear Information System (INIS)

    Pereira, Claudio M.N.A.; Lapa, Celso M.F.

    2003-01-01

    This work extends the research related to generic algorithms (GA) in core design optimization problems, which basic investigations were presented in previous work. Here we explore the use of the Island Genetic Algorithm (IGA), a coarse-grained parallel GA model, comparing its performance to that obtained by the application of a traditional non-parallel GA. The optimization problem consists on adjusting several reactor cell parameters, such as dimensions, enrichment and materials, in order to minimize the average peak-factor in a 3-enrichment zone reactor, considering restrictions on the average thermal flux, criticality and sub-moderation. Our IGA implementation runs as a distributed application on a conventional local area network (LAN), avoiding the use of expensive parallel computers or architectures. After exhaustive experiments, taking more than 1500 h in 550 MHz personal computers, we have observed that the IGA provided gains not only in terms of computational time, but also in the optimization outcome. Besides, we have also realized that, for such kind of problem, which fitness evaluation is itself time consuming, the time overhead in the IGA, due to the communication in LANs, is practically imperceptible, leading to the conclusion that the use of expensive parallel computers or architecture can be avoided

  14. Open problems in reprocessing of a molten salt reactor fuel

    International Nuclear Information System (INIS)

    Lelek, Vladimir; Vocka, Radim

    2000-01-01

    The study of fuel cycle in a molten salt reactor (MSR) needs deeper understanding of chemical methods used for reprocessing of spent nuclear fuel and preparation of MSR fuel, as well as of the methods employed for reprocessing of MSR fuel itself. Assuming that all the reprocessing is done on the basis of electrorefining, we formulate some open questions that should be answered before a flow sheet diagram of the reactor is designed. Most of the questions concern phenomena taking place in the vicinity of an electrode, which influence the efficiency of the reprocessing and sensibility of element separation. Answer to these questions would be an important step forward in reactor set out. (Authors)

  15. Mines vs reactors: comparison of radiation problems and solutions

    International Nuclear Information System (INIS)

    Bush, W.R.

    1981-01-01

    Radiation protection in uranium mines and nuclear reactors is compared, with the objective of determining if any radiation protection practices which have worked well in one area can be adapted to the other area, especially from reactors to mines since radiation protection is more highly developed in reactors. Several areas are identified where improvements can be made in radiation protection in mines, the most important being improvement in ventilation at the workplace, greater attention to special monitoring during upset conditions, and a need for a substantial increase in radiation protection staff. It is concluded that, although considerable room exists for improvement, the general approach to radiation protection presently being followed seems appropriate for the circumstances encountered in mining

  16. Reactor cavity streaming: the problem and engineered solutions

    International Nuclear Information System (INIS)

    Iotti, R.C.; Yang, T.L.; Rogers, W.H.

    1979-01-01

    Experience at operating pressurized water reactors has revealed that air gaps between the reactor vessel and the biological shield wall can provide paths for radiation streaming, which may prohibitively limit the accessibility required to areas in the containment during power operation, increase personnel exposure during shutdown, and cause radiation damage to equipment and cables located above the vessel. Several concepts of shield are discussed together with their predicted effectiveness. The analytical methods employed to determine the streaming magnitude and the shield effectiveness are also discussed and their accuracy is measured by comparison with actual measurement at an operating plant

  17. Ratcheting problems for ITER [International Thermonuclear Experimental Reactor

    International Nuclear Information System (INIS)

    Majumdar, S.

    1991-01-01

    Because of the presence of high cyclic thermal stress, pressure-induced primary stress, and disruption-induced high cyclic primary stress, ratcheting of the first wall poses a serious challenge to the designers of ITER (International Thermonuclear Experimental Reactor). Existing design tools such as the Bree diagram in the ASME Boiler and Pressure Vessels Code, are not directly applicable to ITER, because of important differences in geometry and loading modes. Available alternative models for ratcheting are discussed and new Bree diagrams, that are more relevant for fusion reactor applications, are proposed. 9 refs., 17 figs

  18. Radiological monitoring related to the operation of PUSPATI's Triga Reactor

    International Nuclear Information System (INIS)

    Fatimah Mohamad Amin; Mohamad Yusof Mohamad Ali; Lau How Mooi; Idris Besar.

    1983-01-01

    Reactor operation is one of the main activities carried out at the Tun Ismail Atomic Research Centre (PUSPATI) which requires radiological monitoring. This paper describes the programme for radiological monitoring which is related to the operation of the 1 MW Triga MK II research reactor which was commissioned in July, 1982. This programme includes monitoring of the radiation and contamination levels of the reactor and its associated facilities and environmental monitoring of PUSPATI's site and its environs. The data presented in this paper covers the period between 1982 to 1983 which includes both the pre-operational and operational phases of the monitoring programme. (author)

  19. Problems related to fossil fuels utilization

    International Nuclear Information System (INIS)

    Rota, R.

    1999-01-01

    Fossil fuels still present the main energy source in the world since about 90% of the energy produced comes from combustion. This paper, based on the lectures given at the conference of Energy and Environment hold at the Accademia dei Lincei in 1998, presents a short review of some of the problems related to the utilization of fossil fuels, such as their availability in the medium period, the effect of pollutant dispersion in the atmosphere as well as the available technologies to deal with such problems [it

  20. The fusion reactor - a chance to solve the energy problem

    International Nuclear Information System (INIS)

    Wienecke, R.

    1975-01-01

    The work deals with the physical fundamentals of nuclear fusion and the properties of the necessary plasma and gives a survey on the arrangements used today for magnetic confinement such as tokamak, stellarator, high-beta experiments and laser fusion. Finally, the technology of the fusion reactor and its potential advantages are explained. (RW/LH) [de

  1. Energy problem and harmony in international relations

    International Nuclear Information System (INIS)

    Ogata, Akira

    1975-01-01

    Energy problems and harmony in international relation are closely related with world politics. Oil is destined to remain as the primary energy source for the time being. The situation of oil has different implications to the U.S. and U.S.S.R., oil producing countries, and consumer countries. The hasty attitude in the past to attain energy sufficiency must be avoided by all means. Congenial harmony is to be established in international relation to meet world energy requirement. This also applies to the case of nuclear power in future. (Mori, K.)

  2. Problems of space-time behaviour of nuclear reactors; Problemi prostorno-vremenskog ponasanja nuklearnih reaktora

    Energy Technology Data Exchange (ETDEWEB)

    Obradovic, D [Institut za nuklearne nauke ' Boris Kidric' , Vinca, Belgrade (Yugoslavia)

    1966-07-01

    This paper covers a review of literature and mathematical methods applied for space-time behaviour of nuclear reactors. The review of literature is limited to unresolved problems and trends of actual research in the field of reactor physics. Dat je pregled literature i matematickih metoda koje se koriste prilikom tretiranja prostorno-vremenskog ponasanja nuklearnih reaktora. Pregled literature ogranicen je na jos neresene probleme i pravce u kojima su danas usmerena istrazivanja u ovoj oblasti fizike nuklearnih reaktora (author)

  3. Wishful thinking and real problems: Small modular reactors, planning constraints, and nuclear power in Jordan

    International Nuclear Information System (INIS)

    Ramana, M.V.; Ahmad, Ali

    2016-01-01

    Jordan plans to import two conventional gigawatt scale nuclear reactors from Russia that are expensive and too large for Jordan's current electricity grid. Jordan efforts to establish nuclear power might become easier in some ways if the country were to construct Small Modular Reactors, which might be better suited to Jordan's financial capabilities and its smaller electrical grid capacity. But, the SMR option raises new problems, including locating sites for multiple reactors, finding water to cool these reactors, and the higher cost of electricity generation. Jordan's decision has important implications for its energy planning as well as for the market for SMRs. - Highlights: •Jordan is planning to purchase two large reactors from Russia. •Large reactors would be inappropriate to Jordan's small electricity grid. •Small modular reactors would be more appropriate to Jordan's grid, but have problems. •The market for small modular reactors will be smaller than often projected. •Jordan should consider the financial impact of building a large nuclear reactor.

  4. Molten salt reactor related research in Switzerland

    International Nuclear Information System (INIS)

    Krepel, Jiri; Hombourger, Boris; Fiorina, Carlo

    2015-01-01

    Switzerland represented by the Paul Scherrer Institute (PSI) is a member of the Generation IV International Forum (GIF). In the past, the research at PSI focused mainly on HTR, SFR, and GFR. Currently, a research program was established also for Molten Salt Reactors (MSR). Safety is the key point and main interest of the MSR research at the Nuclear Energy and Safety (NES) department of PSI. However, it cannot be evaluated without knowing the system design, fuel chemistry, salt thermal-hydraulics features, safety and fuel cycle approach, and the relevant material and chemical limits. Accordingly, sufficient knowledge should be acquired in the other individual fields before the safety can be evaluated. The MSR research at NES may be divided into four working packages (WP): WP1: MSR core design and fuel cycle, WP2: MSR fuel behavior at nominal and accidental conditions, WP3: MSR thermal-hydraulics and decay heat removal system, WP4: MSR safety, fuel stream, and relevant limits. The WPs are proposed so that there are research topics which can be independently studied within each of them. The work plan of the four WPs is based on several ongoing or past national and international projects relevant to MSR, where NES/PSI participates. At the current stage, the program focuses on several specific and design independent studies. The safety is the key point and main long-term interest of the MSR research at NES. (author)

  5. Shift work-related health problems in

    Directory of Open Access Journals (Sweden)

    S. Khavaji

    2010-04-01

    Full Text Available Background and aimsShift work is a major feature of working life that affects diverse aspects of human life. The main purposes of this study were to investigate shift work-related health problems and their risk factors among workers of "12-hour shift" schedule.MethodsThis cross-sectional study was carried out at 8 petrochemical industries in Asalooyeh area. Study population consisted of 1203 workers including 549 shift worker (46% and 654 day worker (54%. Data on personal details, shift schedule and adverse effects of shift work werecollected by anonymous questionnaire. Statistical analyses were performed using SPSS, version 11.5. The level of significance was set at 5%.ResultsAlthough, the results showed that health problems among shift workers was more prevalent than day workers, but the differences were just significant in gastrointestinal and musculoskeletal disorders (p<0.05. Multiple linear regressions indicated that in addition to shift working, other variants such as long work hours, type of employment, second job, number of children and job title were associated with health problems.ConclusionPrevalence rates of gastrointestinal and musculoskeletal problems among shift workers were significantly higher than that of day workers. Although, working in shift system was the main significant factor associated with the reported problems, but other demographic andwork variables were also found to have association.

  6. Ageing problems and renovation programme of ET-RR-1 reactor

    International Nuclear Information System (INIS)

    Khattab, M.S.; Sultan, M.A.

    1995-01-01

    Based on Practical Experience gained from interfacing ageing systems in addition to operating new systems, current problems could be deduced whenever in-service inspection are carried out. This paper summarizes the in-service inspection made, and the proposed programme of rehabilitation of mechanical system in the ET-RR-1 research reactor at Inshass. Exchangeable experience in solving common problems in similar reactors play an important role in the effectiveness of such rehabilitation programme. The paper summarizes also the modernization of control, measuring and radiation monitoring system already carried out at the reactor. (orig.)

  7. Current safety issues related to research reactor operation

    International Nuclear Information System (INIS)

    Alcala-Ruiz, F.

    2000-01-01

    The Agency has included activities on research reactor safety in its Programme and Budget (P and B) since its inception in 1957. Since then, these activities have traditionally been oriented to fulfil the Agency's functions and obligations. At the end of the decade of the eighties, the Agency's Research Reactor Safety Programme (RRSP) consisted of a limited number of tasks related to the preparation of safety related publications and the conduct of safety missions to research reactor facilities. It was at the beginning of the nineties when the RRSP was upgraded and expanded as a subprogramme of the Agency's P and B. This subprogramme continued including activities related to the above subjects and started addressing an increasing number of issues related to the current situation of research reactors (in operation and shut down) around the world such as reactor ageing, modifications and decommissioning. The present paper discusses some of the above issues as recognised by various external review or advisory groups (e.g., Peer Review Groups under the Agency's Performance Programme Appraisal System (PPAS) or the standing International Nuclear Safety Advisory Group (INSAG)) and the impact of their recommendations on the preparation and implementation of the part of the Agency's P and B relating to the above subject. (author)

  8. On application of CFD codes to problems of nuclear reactor safety

    International Nuclear Information System (INIS)

    Muehlbauer, Petr

    2005-01-01

    The 'Exploratory Meeting of Experts to Define an Action Plan on the Application of Computational Fluid Dynamics (CFD) Codes to Nuclear Reactor Safety Problems' held in May 2002 at Aix-en-Province, France, recommended formation of writing groups to report the need of guidelines for use and assessment of CFD in single-phase nuclear reactor safety problems, and on recommended extensions to CFD codes to meet the needs of two-phase problems in nuclear reactor safety. This recommendations was supported also by Working Group on the Analysis and Management of Accidents and led to formation oaf three Writing Groups. The first writing Group prepared a summary of existing best practice guidelines for single phase CFD analysis and made a recommendation on the need for nuclear reactor safety specific guidelines. The second Writing Group selected those nuclear reactor safety applications for which understanding requires or is significantly enhanced by single-phase CFD analysis, and proposed a methodology for establishing assesment matrices relevant to nuclear reactor safety applications. The third writing group performed a classification of nuclear reactor safety problems where extension of CFD to two-phase flow may bring real benefit, a classification of different modeling approaches, and specification and analysis of needs in terms of physical and numerical assessments. This presentation provides a review of these activities with the most important conclusions and recommendations (Authors)

  9. Piping benchmark problems for the General Electric Advanced Boiling Water Reactor

    International Nuclear Information System (INIS)

    Bezler, P.; DeGrassi, G.; Braverman, J.; Wang, Y.K.

    1993-08-01

    To satisfy the need for verification of the computer programs and modeling techniques that will be used to perform the final piping analyses for an advanced boiling water reactor standard design, three benchmark problems were developed. The problems are representative piping systems subjected to representative dynamic loads with solutions developed using the methods being proposed for analysis for the advanced reactor standard design. It will be required that the combined license holders demonstrate that their solutions to these problems are in agreement with the benchmark problem set

  10. An holistic approach to the problem of reactor ageing

    International Nuclear Information System (INIS)

    Phythian, W.; McElroy, R.; Druce, S.; Kovan, D.

    1992-01-01

    Understanding the process of ageing in reactors is essential to extending their lives beyond original design. To present a sound case -particularly regarding the level of embrittlement in reactor vessels due to radiation damage - an integrated approach using advanced assessment tools is needed. The techniques developed for the purpose involve, on the microscopic level, advanced neutron dosimetry and high resolution measurement techniques (eg advanced electron beam techniques and small angle neutron scattering) with which an analysis can be done of the radiation damage and the microstructural state of the steel test procedures (tensile, fracture toughness and Charpy impact) on standard and sub-sized specimens, the extent of radiation degradation can be characterised. finally, it is possible to predict how the degradation will evolve using physically-based models of embrittlement. (Author)

  11. Raw materials problems in connection with fast breeder type reactors

    International Nuclear Information System (INIS)

    Hirsch, H.; Kreusch, J.

    1981-01-01

    The power supply by the FBR type reactors which depends upon the availability of essential raw materials such as Cr and Mo for structural and special steels is supposed to be less ensured than supply by fossil-fueled power plants. This contribution tries to verify this statement by means of estimates of the annual Cr and Mo demand, of the resources, production and consumption as well as by a study of the possibilities of recycling and substituting Cr and Mo. The only realistic alternative to the fast breeder type reactor is supposed to be a soft path of development according to the principle of decentralization, utilization of renewable energy sources regard to environmental protection, and use of less sophisticated technology. (DG) [de

  12. The problem of helium in structural materials for fusion reactor

    International Nuclear Information System (INIS)

    Nikiforov, A.S.; Zakharov, A.P.; Chuev, V.I.

    1982-01-01

    The processes of helium buildup in some metals and alloys at different energy neutron flux irradiation under thermonuclear reactor conditions are considered. The data on high temperature helium embrittlement of a number of stainless steels, titanium and aluminium alloys etc. are given A review of experiments concerning the implanted helium behaviour is presented. Possible reactions between helium atoms and point defects or their clusters are discussed. Analysed are material structure variations upon buildup in them up to 1 at % of helium

  13. Triboengineering problems of lead coolant in innovative fast reactors

    International Nuclear Information System (INIS)

    Beznosov, A.V.; Novozhilova, O.O.; Shumilkov, A.I.; Lvov, A.V.; Bokova, T.A.; Makhov, K.A.

    2013-01-01

    Graphical abstract: Models of experimental sites for research of processes tribology in heavy liquid metal coolant. -- Highlights: • The contact a pair of heavy liquid metal coolant for reactors on fast neutrons. • The hydrostatic bearings main circulation pumps. • Oxide coating and degree of wear of friction surfaces in heavy liquid metal coolant. -- Abstract: So far, there are plenty of works dedicated to studying the phenomenon of friction. However, there are none dedicated to functioning of contact pairs in heavy liquid-metal coolants for fast neutron, reactor installations (Kogaev and Drozdov, 1991; Modern Tribology, 2008; Drozdov et al., 1986). At the Nizhny Novgorod State Technical University, such research is conducted in respect to friction, bearings of main circulating pumps, interaction of sheaths of neutron absorber rods with their covers, of the reactor control and safety system, refueling systems, and interaction of coolant flows with, channel borders. As a result of experimental studies, the characteristic of friction pairs in the heavy, liquid metal coolant shows the presence dependences of oxide film on structural materials of the wear. The inapplicability of existing calculation methods for assessing the performance of the bearing nodes, in the heavy liquid metal coolant is shown

  14. IAEA activities related to research reactor fuel conversion and spent fuel return programmes

    International Nuclear Information System (INIS)

    Ritchie, I.G.; Adelfang, P.; Goldman, I.N.

    2004-01-01

    Full text: The IAEA has been involved for more than twenty years in supporting international nuclear non-proliferation efforts associated with reducing the amount of highly enriched uranium (HEU) in international commerce. IAEA projects and activities have directly supported the Reduced Enrichment for Research and Test Reactors (RERTR) programme, as well as directly associated efforts to return research reactor fuel to the country of origin where it was originally enriched. IAEA efforts have included the development and maintenance of several data bases with information related to research reactors and research reactor spent fuel inventories that have been essential in planning and managing both RERTR and spent fuel return programmes. Other IAEA regular budget programmes have supported research reactor fuel conversion from HEU to low enriched uranium, and in addressing issues common to many member states with spent fuel management problems and concerns. The paper briefly describes IAEA involvement since the early 1980's in these areas, including regular budget and Technical Co-operation programme activities, and focuses on efforts in the past five years to continue to support and accelerate U.S. and Russian research reactor spent fuel return programmes. It is hoped that an announcement of the extension of the U.S. Acceptance Programme, which is expected in the very near future, will facilitate the life extensions of many productive TRIGA reactors around the world. (author)

  15. Benchmark problem suite for reactor physics study of LWR next generation fuels

    International Nuclear Information System (INIS)

    Yamamoto, Akio; Ikehara, Tadashi; Ito, Takuya; Saji, Etsuro

    2002-01-01

    This paper proposes a benchmark problem suite for studying the physics of next-generation fuels of light water reactors. The target discharge burnup of the next-generation fuel was set to 70 GWd/t considering the increasing trend in discharge burnup of light water reactor fuels. The UO 2 and MOX fuels are included in the benchmark specifications. The benchmark problem consists of three different geometries: fuel pin cell, PWR fuel assembly and BWR fuel assembly. In the pin cell problem, detailed nuclear characteristics such as burnup dependence of nuclide-wise reactivity were included in the required calculation results to facilitate the study of reactor physics. In the assembly benchmark problems, important parameters for in-core fuel management such as local peaking factors and reactivity coefficients were included in the required results. The benchmark problems provide comprehensive test problems for next-generation light water reactor fuels with extended high burnup. Furthermore, since the pin cell, the PWR assembly and the BWR assembly problems are independent, analyses of the entire benchmark suite is not necessary: e.g., the set of pin cell and PWR fuel assembly problems will be suitable for those in charge of PWR in-core fuel management, and the set of pin cell and BWR fuel assembly problems for those in charge of BWR in-core fuel management. (author)

  16. Current problems of VVER-1000 reactor core operation in Ukraine

    International Nuclear Information System (INIS)

    Bykov, A.

    2000-01-01

    Planned control rod drop time registration was passed two times a year per reactor unit. In 1992-1993 some control rods at almost all WWER-1000 units exceed the prescribed 4 second time limit. More than 7000 individual control rod time tests were made from the main correction measures. The following conclusions have been made from the current statistics data: (a) The main role of the vibration factor is proven in the fuel assembly (FA) bowing process. The greatest drop times and maximum of bowing values are concentrated at the vibration zone (2-4 FA rows from the reactor partition). The first FA row seems to be stable due to the interaction with the reactor partition; (b) Bowing relaxation will proceed during several fuel cycles (estimated value is 4-6), and depends on previous FA use history. It seems to be proven that previously bowed FAs effect the new FA, so previously bowed FAs are straightened until the middle of the fuel cycle. At some reactor units small drop time reduction is observed up to half of the fuel cycle from the start time values; (c) Control rod drop medium time (t) has almost linear dependence on operation time (τ) (t=k x τ + b]. Estimated by the method of least squares, values of k and b differ from unit to unit and from cycle to cycle. Values of k and b are in following ranges: b=2.0 - 2.6 seconds, k=5-50x10 -4 seconds per effective operation day; (d) Control rod drop time distribution changes through operation time. The position of maximum starts to shift after 240 effective days, and the form of the distribution start to change at the same time. Before 240 effective days, the distribution essentially does not change. To guarantee that the control rod system reliability is now within prescribed limits, we should continue testing. Additional analysis is needed. Test frequency can be reduced to avoid additional unreasonable transients. (authors)

  17. On the use Pontryagin's maximum principle in the reactor profiling problem

    International Nuclear Information System (INIS)

    Silko, P.P.

    1976-01-01

    The optimal given power profile approximation problem in nuclear reactors is posed as one of physical profiling problems in terms of the theory of optimal processes. It is necessary to distribute the concentration of the profiling substance in a certain nuclear reactor in such a way that the power profile obtained in the core would be as near as possible to the given profile. It is suggested that the original system of differential equations describing the behaviour of neutrons in a reactor and some applied requirements may be written in the form of usual differential equations of the first order. The integral quadratic criterion evaluating a deviation of the power profile obtained in a reactor from the given one is used as a purpose function. The initial state is given, the control aim is determined as the necessity of transfer of a control object from the initial state to the given set of finite states known as a purpose set. A class of permissible controls consists of measurable functions in the given range. On solving the formulated problem Pontryagin's maximum principle is used. As an example, the power profile flattening problem is considered, for which a program in Fortran-4 for the 'Minsk-32' computer has been written. The optimal reactor parameters calculated by this program at various boundary values of the control are presented. It is noticed that a type of the optimal reactor configuration depends on boundary values of the control

  18. Age-related degradation of boiling water reactor vessel internals

    International Nuclear Information System (INIS)

    Ware, A.G.; Shah, V.N.

    1992-01-01

    Researchers at the Idaho National Engineering Laboratory performed an assessment of the aging of the reactor internals in boiling water reactors (BWRs), and identified the unresolved technical issues related to the degradation of these components. The overall life-limiting mechanism is intergranular stress corrosion cracking (IGSCC). Irradiation-assisted stress corrosion cracking, fatigue, and thermal aging embrittlement are other potential degradation mechanisms. Several failures in BWR internals have been caused by a combination of factors such as environment, high residual or preload stresses, and flow-induced vibration. The ASME Code Section XI in-service inspection requirements are insufficient for detecting aging-related degradation at many locations in reactor internals. Many of the potential locations for IGSCC or fatigue are not accessible for inspection. (orig.)

  19. Solutions for Foaming Problems in Biogas Reactors Using Natural Oils or Fatty Acids as Defoamers

    DEFF Research Database (Denmark)

    Kougias, Panagiotis; Boe, Kanokwan; Angelidaki, Irini

    2015-01-01

    Foaming is one of the most common and important problems in biogas plants, leading to severe operational, economical, and environmental drawbacks. Because addition of easily degradable co-substrates for boosting the biogas production can suddenly raise the foaming problem, the full-scale biogas...... results from our previous extensive research along with some unpublished data on defoaming by rapeseed oil and oleic acid in manure-based biogas reactors. It was found that both compounds exhibited remarkable defoaming efficiency ranging from 30 to 57% in biogas reactors suffering from foaming problems...... promoted by the addition of protein, lipid, or carbohydrate co-substrates. However, in most cases, the defoaming efficiency of rapeseed oil was greater than that of oleic acid, and therefore, rapeseed oil is recommended to be used in biogas reactors to solve foaming problems....

  20. Relative locality and the soccer ball problem

    International Nuclear Information System (INIS)

    Amelino-Camelia, Giovanni; Freidel, Laurent; Smolin, Lee; Kowalski-Glikman, Jerzy

    2011-01-01

    We consider the behavior of macroscopic bodies within the framework of relative locality [G. Amelino-Camelia, L. Freidel, J. Kowalski-Glikman, and L. Smolin, arXiv:1101.0931]. This is a recent proposal for Planck scale modifications of the relativistic dynamics of particles which are described as arising from deformations in the geometry of momentum space. We consider and resolve a common objection against such proposals, which is that, even if the corrections are small for elementary particles in current experiments, they are huge when applied to composite systems such as soccer balls, planets, and stars, with energies E macro much larger than M P . We show that this soccer ball problem does not arise within the framework of relative locality because the nonlinear effects for the dynamics of a composite system with N elementary particles appear at most of order E macro /N·M P .

  1. Preliminary Results Of LOCA Problem For APR1400 Reactor

    International Nuclear Information System (INIS)

    Le Dai Dien; Hoang Minh Giang; Le Thi Thu; Vo Thi Huong; Le Van Hong

    2011-01-01

    Several features of NPP with APR1400 nuclear reactor during a loss of coolant accident (LOCA) are investigated in this study. The report describes some main design characteristics of an engineering safety systems of APR1400 and the thermal hydraulic calculation results for steady-state using MARS and RELAP/SCDAPSIM codes. Large Break LOCA accident has been analyzed and evaluated based on acceptable criteria for ECCS given by US NRC. The results from cold leg break LOCA with broken area of 0.0465 m 2 in case of high pressure safety injection system (HPSI) failed to operate or 2 and 4 HPSI pumps are activated. The preliminary results of this work is a part of collaboration between INST researchers and KAERI experts in using RELAP tool for safety analysis of NPPs. (author)

  2. Multiphase flow problems on thermofluid safety for fusion reactors

    International Nuclear Information System (INIS)

    Takase, Kazuyuki

    2003-01-01

    As the thermofluid safety study for the International Thermonuclear Experimental Reactor (ITER), thermal-hydraulic characteristics of Tokamak fusion reactors under transient events were investigated experimentally and analyzed numerically. As severe transient events an ingress-of-coolant event (ICE) and a loss-of-vacuum event (LOVA) were considered. An integrated ICE test facility was constructed to demonstrate that the ITER safety design approach and parameters are adequate. Water-vapor two-phase flow behavior and performance of the ITER pressure suppression system during the ICE were clarified by the integrated ICE experiments. The TRAC was modified to specify the two-phase flow behavior under the ICE. The ICE experimental results were verified using the modified TRAC code. On the other hand, activated dust mobilization and air ingress characteristics in the ITER vacuum vessel during the LOVA were analyzed using a newly developed analysis code. Some physical models on the motion of dust were considered. The rate of dust released from the vacuum vessel through breaches to the outside was characterized quantitatively. The predicted average pressures in the vacuum vessel during the LOVA were in good agreement with the experimental results. Moreover, direct-contact condensation characteristics between water and vapor inside the ITER suppression tank were observed visually and simulated by the direct two-phase flow analysis. Furthermore, chemical reaction characteristics between vapor and ITER plasma-facing component materials were predicted numerically in order to obtain qualitative estimation on generation of inflammable gases such as hydrogen and methane. The experimental and numerical results of the present studies were reflected in the ITER thermofluid safety design. (author)

  3. Safety-related parameters for the MAPLE research reactor and a comparison with the IAEA generic 10-MW research reactor

    International Nuclear Information System (INIS)

    Carlson, P.A.; Lee, A.G.; Smith, H.J.; Ellis, R.J.

    1989-07-01

    A summary is presented of some of the principle safety-related physics parameters for the MAPLE Research Reactor, and a comparison with the IAEA Generic 10-MW Reactor is given. This provides a means to assess the operating conditions and fuelling requirements for safe operation of the MAPLE Research Reactor under accepted standards

  4. An investigation of the closure problem applied to reactor accident source terms

    International Nuclear Information System (INIS)

    Brearley, I.R.; Nixon, W.; Hayns, M.R.

    1987-01-01

    The closure problem, as considered here, focuses attention on the question of when in current research programmes enough has been learned about the source terms for reactor accident releases. Noting that current research is tending to reduce the estimated magnitude of the aerosol component of atmospheric, accidental releases, several possible criteria for closure are suggested. Moreover, using the reactor accident consequence model CRACUK, the effect of gradually reducing the aerosol release fractions of a pressurized water reactor (PWR2) source term (as defined in the WASH-1400 study) is investigated and the implications of applying the suggested criteria to current source term research discussed. (author)

  5. OECD Nuclear Energy Agency Activities Related to Fast Reactor Development

    International Nuclear Information System (INIS)

    Dujardin, Thierry; Gulliford, Jim

    2013-01-01

    • Despite impact of Fukushima, there remains a high level of interest in continued development of advanced nuclear systems and fuel cycles: – better use of natural resources; – minimisation of waste and reduction of constraints on deep geological repositories. • Ambitious R&D programmes on-going at national level in many countries, also through international projects: – expected to lead to development of advanced reactors and fuel cycle facilities. • OECD/NEA will continue to support member countries in field of fast reactor development and related advanced fuel cycles: – forum for exchange of information; – collaborative activities

  6. General description of preliminary design of an experimental fusion reactor and the future problems

    International Nuclear Information System (INIS)

    Sako, Kiyoshi

    1976-01-01

    Recently, the studies on plasma physics has progressed rapidly, and promising experimental data emerged successively. Especially expectation mounts high that Tokamak will develop into power reactors. In Japan, the construction of large plasma devices such as JT-60 of JAERI is going to start, and after several years, the studies on plasma physics will come to the end of first stage, then the main research and development will be directed to power reactors. The studies on the design of practical fusion reactors have been in progress since 1973 in JAERI, and the preliminary design is being carried out. The purposes of the preliminary design are the clarification of the concept of the experimental reactor and the requirements for the studies on core plasma, the examination of the problems for developing main components and systems of the reactor, and the development of design technology. The experimental reactor is the quasi-steady reactor of 100 MW fusion reaction output, and the conditions set for the design and the basis of their setting are explained. The outline of the design, namely core plasma, blankets, superconductive magnets and the shielding with them, vacuum wall, neutral particle injection heating device, core fuel supply and exhaust system, and others, is described. In case of scale-up the reactor structural material which can withstand neutron damage must be developed. (Kako, I.)

  7. Solution of a benchmark set problems for BWR and PWR reactors with UO2 and MOX fuels using CASMO-4

    International Nuclear Information System (INIS)

    Martinez F, M.A.; Valle G, E. del; Alonso V, G.

    2007-01-01

    In this work some of the results for a group of benchmark problems of light water reactors that allow to study the physics of the fuels of these reactors are presented. These benchmark problems were proposed by Akio Yamamoto and collaborators in 2002 and they include two fuel types; uranium dioxide (UO 2 ) and mixed oxides (MOX). The range of problems that its cover embraces three different configurations: unitary cell for a fuel bar, fuel assemble of PWR and fuel assemble of BWR what allows to carry out an understanding analysis of the problems related with the fuel performance of new generation in light water reactors with high burnt. Also these benchmark problems help to understand the fuel administration in core of a BWR like of a PWR. The calculations were carried out with CMS (of their initials in English Core Management Software), particularly with CASMO-4 that is a code designed to carry out analysis of fuels burnt of fuel bars cells as well as fuel assemblies as much for PWR as for BWR and that it is part in turn of the CMS code. (Author)

  8. One-dimensional computational modeling on nuclear reactor problems

    International Nuclear Information System (INIS)

    Alves Filho, Hermes; Baptista, Josue Costa; Trindade, Luiz Fernando Santos; Heringer, Juan Diego dos Santos

    2013-01-01

    In this article, we present a computational modeling, which gives us a dynamic view of some applications of Nuclear Engineering, specifically in the power distribution and the effective multiplication factor (keff) calculations. We work with one-dimensional problems of deterministic neutron transport theory, with the linearized Boltzmann equation in the discrete ordinates (SN) formulation, independent of time, with isotropic scattering and then built a software (Simulator) for modeling computational problems used in a typical calculations. The program used in the implementation of the simulator was Matlab, version 7.0. (author)

  9. Safety of pressurized water reactors: problems and corresponding studies

    International Nuclear Information System (INIS)

    Cogne, F.

    1976-01-01

    The author recalls the safety problems subject to researches in the CEA, either because of their importance or because studies made abroad were not sufficiently developed or were classified or in order to acquire an independent judgement when safety is concerned. Those problems and studies are submitted referring to the 3 existing shields between man and dangerous materials: fuel element can, thermal shield, (pressure vessel and pipes), biological shield of which the behaviour is studied in connection with outside aggressions such as earthquakes, plane crashes, chemical explosions.. [fr

  10. IAEA activities related to research reactor fuel conversion and spent fuel return programs

    International Nuclear Information System (INIS)

    Goldman, Ira N.; Adelfang, Pablo; Ritchie, Iain G.

    2005-01-01

    The IAEA has been involved for more than twenty years in supporting international nuclear non-proliferation efforts associated with reducing the amount of highly enriched uranium (HEU) in international commerce. IAEA projects and activities have directly supported the Reduced Enrichment for Research and Test Reactors (RERTR) programme, as well as directly associated efforts to return research reactor fuel to the country where it was originally enriched. IAEA efforts have included the development and maintenance of several data bases with information related to research reactors and research reactor spent fuel inventories that have been essential in planning and managing both RERTR and spent fuel return programmes. Other IAEA regular budget programs have supported research reactor fuel conversion from HEU to low enriched uranium (LEU), and in addressing issues common to many member states with spent fuel management problems and concerns. The paper briefly describes IAEA involvement since the early 1980's in these areas, including regular budget and Technical Co-operation programme activities, and focuses on efforts in the past five years to continue to support and accelerate U.S. and Russian research reactor spent fuel return programmes. (author)

  11. Development of numerical methods for thermohydraulic problems in reactor safety

    International Nuclear Information System (INIS)

    Chabrillac, M.; Kavenoky, A.; Le Coq, G.; L'Heriteau, J.P.; Stewart, B.; Rousseau, J.C.

    1976-01-01

    Numerical methods are being developed for the LOCA calculation; the first part is devoted to the BERTHA model and the associated characteristic treatment for the first seconds of the blowdown, the second part presents the problems encountered for accounting for velocity difference between phases. The FLIRA treatment of the reflooding is presented in the last part: this treatment allows the calculation of the quenching front velocity

  12. To the problem of reinforced concrete reactor vessel design and calculation

    International Nuclear Information System (INIS)

    Kirillov, A.P.; Artem'ev, V.P.; Bogopol'skij, V.G.; Nikolaev, Yu.B.; Paushkin, A.G.

    1980-01-01

    Modern methods for calculating reactor vessels of prestressed reinforced concrete are analyzed. It is shown that during the stage of technical and economical substantiation of reactor vessel structure for determining its stressed-deformed state engineering methods of calculation must be used, in particular, fragmentation method, method of rings and plates, and during the stages of contract and detail designs - method of finite elements and dynamic relaxation method. It is concluded that when solving cyclic symmetrical problems as well as asymmetrical problems, calculational algorithms for axis-symmetrical distributions of stresses in the vessel with provision for elastic properties of structural material may be used

  13. Iterative solution to the optimal poison management problem in pressurized water reactors

    International Nuclear Information System (INIS)

    Colletti, J.P.; Levine, S.H.; Lewis, J.B.

    1983-01-01

    A new method for solving the optimal poison management problem for a multiregion pressurized water reactor has been developed. The optimization objective is to maximize the end-of-cycle core excess reactivity for any given beginning-of-cycle fuel loading. The problem is treated as an optimal control problem with the region burnup and control absorber concentrations acting as the state and control variables, respectively. Constraints are placed on the power peaking, soluble boron concentration, and control absorber concentrations. The solution method consists of successive relinearizations of the system equations resulting in a sequence of nonlinear programming problems whose solutions converge to the desired optimal control solution. Application of the method to several test problems based on a simplified three-region reactor suggests a bang-bang optimal control strategy with the peak power location switching between the inner and outer regions of the core and the critical soluble boron concentration as low as possible throughout the cycle

  14. Relating Actor Analysis Methods to Policy Problems

    NARCIS (Netherlands)

    Van der Lei, T.E.

    2009-01-01

    For a policy analyst the policy problem is the starting point for the policy analysis process. During this process the policy analyst structures the policy problem and makes a choice for an appropriate set of methods or techniques to analyze the problem (Goeller 1984). The methods of the policy

  15. Material problems concerning the safety of light water reactors

    International Nuclear Information System (INIS)

    Bocek, M.; Dienst, W.; Hofmann, P.; Leistikow, S.

    The problems dealt with in this lecture and the corresponding investigations refer to the behavior of LWR fuel rods at loss-of-coolant accidents. In the foreground is the deformation of zircaloy 4 cladding until rupture will take place, the following aspects being pointed out: obstruction of emergency cooling of fuel assemblies by heavily deformed cladding tubes, release of radioactive fission products through cracks in the cladding, local fragmentation of the fuel rods caused by extensive embrittlement of the cladding tubes. (orig./IHOE) [de

  16. DESIGN SAFETY PROBLEMS OF NUCLEAR REACTORS IN SPACE FOR ELECTRICAL POWER

    Energy Technology Data Exchange (ETDEWEB)

    Pickler, D A

    1963-06-15

    A general treatment is presented of some of the problems in the design safety of reactors which are to be operated in space. The basic requirements of these reachigh temperatures. The usual concept of a space reactor is described briefly, and the hazards of an assumed unmanned vehicle with an enriched-U-fueled reactor are examined during its launching, orbit, and reentry. Graphs are given for the dose vs distance downwind for an excursion of 100 Mw-sec, for the activity vs time after shutdown of a reactor which has been operated for 5 yr at 100 kw(t), and for the altitude vs orbital lifetime. Apparent conflicts between the basic requirements are discussed. (D.L.C.)

  17. Regulatory problems relating to energy in Hungary

    International Nuclear Information System (INIS)

    Remenyi, K.

    2002-01-01

    One of basic problems of the transition in the energy economy is, how far the process of liberalisation and privatisation could go, i.e. to what extent the control of state/government would be given up, and how the breakdown of the commanding positions of the government would be managed. The transition in the energy sector toward a market economy is characterised by restructuring the regulatory framework of the energy industry, changing the operational structure of the sector and profound reshaping of ownership structures of the enterprises. In Hungary the government, being convinced of the importance of the implementation of the market forces, in 1991 made the first step on the way of restructuring the energy sector in order to increase economic efficiency, to enable companies to react to market forces and to privatise them. Parallel and partly after the restructuring, a profound modification of legal and regulatory framework took place and finally a relatively large scale of privatisation has newly emerged, which will continue in future, too. The process of the energy sector liberalisation in Hungary has a stop and go character and the game is not over. The process can be characterised by institutional restructuring in the energy sector (coal, oil/gas, power ), which is the basic condition for market liberalisation and privatisation, and by the creation of an appropriate environment (regulatory framework, pricing policy, etc. ) for the smooth implementation of the liberation process(author)

  18. Anholonomic Cauchy problem in general relativity

    International Nuclear Information System (INIS)

    Stachel, J.

    1980-01-01

    The Lie derivative approach to the Cauchy problem in general relativity is applied to the evolution along an arbitrary timelike vector field for the case where the dynamical degrees of freedom are chosen as the (generally anholonomic) metric of the hypersurface elements orthogonal to the vector field. Generalizations of the shear, rotation, and acceleration are given for a nonunit timelike vector field, and applied to the three-plus-one breakup of the Riemann tensor into components parallel and orthogonal to the vector field, resulting in the anholonomic Gauss--Codazzi equations. A similar breakup of the Einstein field equations results in the form of the constraint and evolution equations for the anholonomic case. The results are applied to the case of a space--time with a timelike Killing vector field (stationary field) to demonstrate their utility. Other possible applications, such as in the numerical integration of the field equations, are mentioned. Definitions are given of three-index shear, rotation, and acceleration tensors, and their use in a two-plus-two decomposition of the Riemann tensor and field equations is indicated

  19. Solution of the Lambda modes problem of a nuclear power reactor using an h–p finite element method

    International Nuclear Information System (INIS)

    Vidal-Ferrandiz, A.; Fayez, R.; Ginestar, D.; Verdú, G.

    2014-01-01

    Highlights: • An hp finite element method is proposed for the Lambda modes problem of a nuclear reactor. • Different strategies can be implemented for increasing the accuracy of the solutions. • 2D and 3D benchmarks have been studied obtaining accurate results. - Abstract: Lambda modes of a nuclear power reactor have interest in reactor physics since they have been used to develop modal methods and to study BWR reactor instabilities. An h–p-Adaptation finite element method has been implemented to compute the dominant modes the fundamental mode and the next subcritical modes of a nuclear reactor. The performance of this method has been studied in three benchmark problems, a homogeneous 2D reactor, the 2D BIBLIS reactor and the 3D IAEA reactor

  20. Finding Solutions to Different Problems Simultaneously in a Multi-molecule Simulated Reactor

    Directory of Open Access Journals (Sweden)

    Jaderick P. Pabico

    2014-12-01

    Full Text Available – In recent years, the chemical metaphor has emerged as a computational paradigm based on the observation of different researchers that the chemical systems of living organisms possess inherent computational properties. In this metaphor, artificial molecules are considered as data or solutions, while the interactions among molecules are defined by an algorithm. In recent studies, the chemical metaphor was used as a distributed stochastic algorithm that simulates an abstract reactor to solve the traveling salesperson problem (TSP. Here, the artificial molecules represent Hamiltonian cycles, while the reactor is governed by reactions that can re-order Hamiltonian cycles. In this paper, a multi-molecule reactor (MMR-n that simulates chemical catalysis is introduced. The MMR-n solves in parallel three NP-hard computational problems namely, the optimization of the genetic parameters of a plant growth simulation model, the solution to large instances of symmetric and asymmetric TSP, and the static aircraft landing scheduling problems (ALSP. The MMR-n was shown as a computational metaphor capable of optimizing the cultivar coefficients of CERES-Rice model, and at the same time, able to find solutions to TSP and ALSP. The MMR-n as a computational paradigm has a better computational wall clock time compared to when these three problems are solved individually by a single-molecule reactor (MMR-1.

  1. Review of heat transfer problems associated with magnetically-confined fusion reactor concepts

    International Nuclear Information System (INIS)

    Hoffman, M.A.; Werner, R.W.; Carlson, G.A.; Cornish, D.N.

    1976-01-01

    Conceptual design studies of possible fusion reactor configurations have revealed a host of interesting and sometimes extremely difficult heat transfer problems. The general requirements imposed on the coolant system for heat removal of the thermonuclear power from the reactor are discussed. In particular, the constraints imposed by the fusion plasma, neutronics, structure and magnetic field environment are described with emphasis on those aspects which are unusual or unique to fusion reactors. Then the particular heat transfer characteristics of various possible coolants including lithium, flibe, boiling alkali metals, and helium are discussed in the context of these general fusion reactor requirements. Some specific areas where further experimental and/or theoretical work is necessary are listed for each coolant along with references to the pertinent research already accomplished. Specialized heat transfer problems of the plasma injection and removal systems are also described. Finally, the challenging heat transfer problems associated with the superconducting magnets are reviewed, and once again some of the key unsolved heat transfer problems are enumerated

  2. Contribution to the study of thermal-hydraulic problems in nuclear reactors; Contribution a l`etude de problemes de thermohydraulique dans les reacteurs nucleaires

    Energy Technology Data Exchange (ETDEWEB)

    Cognet, G

    1998-07-07

    In nuclear reactors, whatever the type considered, Pressurized Water Water Reactors (PWRs), Fast Breeder reactors (FBRs)..., thermal-hydraulics, the science of fluid mechanics and thermal behaviour, plays an essential role, both in nominal operating and accidental conditions. Fluid can either be the primary fluid (liquid or gas) or a very specific fluid called corium, which, in case of severe accident, could result from core and environning structure melting. The work reported here represents a 20-year contribution to thermal-hydraulic issues which could occur in FBRs and PWRs. Working on these two types of reactors, both in nominal and severe accident situations, has allowed me to compare the problems and to realize the importance of communication between research teams. The evolution in the complexity of studied problems, unavoidable in order to reduce costs and significantly improve safety, has led me from numerical modelling of single-phase flow turbulence to high temperature real melt experiments. The difficulties encountered in understanding the observed phenomena and in increasing experimental databases for computer code qualification have often entailed my participation in specific measurement device developments or adaptations, in particular non-intrusive devices generally based on optical techniques. Being concerned about the end-use of this research work, I actively participated in `in-situ` thermalhydraulic experiments in the FBRs: Phenix and Super-Phenix, of which I appreciated their undeniable scientific contribution. In my opinion, the thermal-hydraulic questions related to severe accidents are the most complex as they are at the cross-roads of several scientific specialities. Consequently, they require a multi-disciplinary approach and a continuous see-saw motion between experimentalists and modelling teams. After a brief description of the various problems encountered, the main ones are reported. Finally, the importance for research teams to

  3. Dismantling of nuclear facilities and related problems - Conference proceedings

    International Nuclear Information System (INIS)

    Tournebize, Frederic; Bordet, Didier; Charlety, Philippe; Gore, Thierry; Estrade, Jerome; Lemaire, Hermine; Ginet, Annick; Fabrier, Lionel; Evrard, Lydie; Furois, Timothee; Butez, Marc; Dutzer, Michel; Faure, Vincent; Billarand, Yann; Menuet, Lise; Lahaye, Thierry; Pin, Alain; Mougnard, Philippe; Charavy, Sylvain; Poncet, Philippe; Moggia, Fabrice; Dochy, Arnaud; Benjamin, Patrick; Poncet, Pierre-Emmanuel; Beneteau, Yannick; Richard, Jean-Baptiste; Pellenz, Gilles; Ollivier Dehaye, Catherine; Gerard, Stephane; Denissen, Luc; Davain, Henri; Duveau, Florent; Guyot, Jean-Luc; Ardellier, Luc

    2012-11-01

    The oldest French nuclear facilities, built for some of them in the 1950's for research or power generation purposes, have reached more or less the end of their life. More than 30 facilities have entered the shutdown or dismantling phase, among which 8 reactors of the very first generations of Electricite de France (EdF) reactors. The aim of this two-days conference is to take stock of the present day status and perspectives of the dismantling activity, to approach the question of the management of the wastes produced, and to share experience about large scale operations already carried out. This document gathers the available presentations given during this conference: 1 - the 'Passage' project (F. Tournebize); 2 - CEA-Grenoble: from Louis Neel to key enabling technologies (D. Bordet); 3 - Dismantling actions in France (L. Evrard); 4 - Securing control of long-term charges funding (T. Furois); 5 - Waste disposal projects and their contribution to the management of dismantling wastes (M. Butez); 6 - Specificities linked with dismantling activities (Y. Billarand); 7 - Dismantling safety: the ASN's point of view (L. Evrad); 8 - Labor Ministry viewpoint about the dismantling related questions (T. Lahaye); 9 - Consideration of organizational and human factors in dismantling operations: a new deal in the operators-service providers relation (L. Menuet); 10 - Diploma and training experience (A. Pin); 11 - Glove-boxes dismantling at La Hague plant - status and experience feedback (P. Mougnard); 12 - Dismantling of Siloe reactor (CEA-Grenoble): application of the ALARA approach (P. Charlety); 13 - BR3 - a complex dismantling: the neutron shield tank (NST) in remote operation and indirect vision (L. Denissen); 14 - Cleansing and dismantling of the Phebus PF containment (S. Charavy); 15 - Integration of dismantling at the design and exploitation stages of nuclear facilities (P. Poncet); 16 - Consideration during the design and exploitation stages of dispositions aiming at

  4. Immediate relation of ING to fast breeder reactor programs

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, W B

    1969-07-01

    The future large-scale use of nuclear energy is linked in the United States and other major countries to their fast breeder reactor development. Very serious basic problems have been discovered within the last two years, limiting the life in the high fast neutron flux at appropriate temperatures of materials, in particular of metals suitable for fuel cladding in sodium coolant. There is therefore a most urgent need for materials testing facilities under controlled conditions of temperature and neutron flux at sufficiently high ratings to match or surpass those required in commercially competitive fast breeder reactors. None of the test facilities yet planned for 1976 or sooner in the western world appears to match these conditions. The problem is mainly the difficulty of providing the high neutron flux effectively continuously. The spallation reaction in heavy elements was chosen as the basis of ING - the intense neutron generator, because it is the only known reaction that promises a fast neutron source density that is higher than can be controlled from the fission process. It is suggested that several countries will wish to consider urgently whether they should also explore the spallation reaction for the purpose of a fast neutron irradiation test facility. In view of the discontinuance of the ING project in Canada a favourable opportunity will exist over the next few months 10 obtain from Canada by direct personal contact details of the significant study that has been carried on for ING over the last five years. In the event that satisfactory materials are established within the lifetime of the spallation facilities they may continue to be used for the production of selected isotopes more profitably produced in high neutron fluxes. The facilities may be also used for the desirable preirradiation of thorium reactor fuel. The other research purposes planned for ING could also be served. (author)

  5. Immediate relation of ING to fast breeder reactor programs

    International Nuclear Information System (INIS)

    Lewis, W.B.

    1969-01-01

    The future large-scale use of nuclear energy is linked in the United States and other major countries to their fast breeder reactor development. Very serious basic problems have been discovered within the last two years, limiting the life in the high fast neutron flux at appropriate temperatures of materials, in particular of metals suitable for fuel cladding in sodium coolant. There is therefore a most urgent need for materials testing facilities under controlled conditions of temperature and neutron flux at sufficiently high ratings to match or surpass those required in commercially competitive fast breeder reactors. None of the test facilities yet planned for 1976 or sooner in the western world appears to match these conditions. The problem is mainly the difficulty of providing the high neutron flux effectively continuously. The spallation reaction in heavy elements was chosen as the basis of ING - the intense neutron generator, because it is the only known reaction that promises a fast neutron source density that is higher than can be controlled from the fission process. It is suggested that several countries will wish to consider urgently whether they should also explore the spallation reaction for the purpose of a fast neutron irradiation test facility. In view of the discontinuance of the ING project in Canada a favourable opportunity will exist over the next few months 10 obtain from Canada by direct personal contact details of the significant study that has been carried on for ING over the last five years. In the event that satisfactory materials are established within the lifetime of the spallation facilities they may continue to be used for the production of selected isotopes more profitably produced in high neutron fluxes. The facilities may be also used for the desirable preirradiation of thorium reactor fuel. The other research purposes planned for ING could also be served. (author)

  6. Dynamic problems of power reactors and analogic devices; Les problemes dynamiques du reacteur de puissance et les machines analogiques

    Energy Technology Data Exchange (ETDEWEB)

    Braffort, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-07-01

    The raise of the nuclear physics came with heavy mathematical developments. The analogical installations became especially useful for precise calculations of parameters which depend the running of a reactor. They permit between other to study of kinetic problems and especially ''cybernetics'' of nuclear reactors. It doesn't make a doubt that their use will become widespread, not only in the calculations laboratories, in services for servo-mechanisms study, but also in the control panels of the reactors themselves. (M.B.) [French] L'essor de la physique nucleaire s'est accompagne de lourds developpements mathematiques. Les montages analogiques sont devenus particulierement utiles pour les calculs precis des parametres dont depend le fonctionnement d'un reacteur. Elles permettent entre autre l'etude des problemes cinetiques et surtout ''cybernetiques'' des reacteurs nucleaires. Il ne fait pas de doute que leur usage se generalisera, non seulement dans les laboratoires de calculs, les services d'etudes de servomecanismes, mais aussi pres des tableaux de commande des reacteurs eux-memes. (M.B.)

  7. FOCUS, Neutron Transport System for Complex Geometry Reactor Core and Shielding Problems by Monte-Carlo

    International Nuclear Information System (INIS)

    Hoogenboom, J.E.

    1980-01-01

    1 - Description of problem or function: FOCUS enables the calculation of any quantity related to neutron transport in reactor or shielding problems, but was especially designed to calculate differential quantities, such as point values at one or more of the space, energy, direction and time variables of quantities like neutron flux, detector response, reaction rate, etc. or averages of such quantities over a small volume of the phase space. Different types of problems can be treated: systems with a fixed neutron source which may be a mono-directional source located out- side the system, and Eigen function problems in which the neutron source distribution is given by the (unknown) fundamental mode Eigen function distribution. Using Monte Carlo methods complex 3- dimensional geometries and detailed cross section information can be treated. Cross section data are derived from ENDF/B, with anisotropic scattering and discrete or continuous inelastic scattering taken into account. Energy is treated as a continuous variable and time dependence may also be included. 2 - Method of solution: A transformed form of the adjoint Boltzmann equation in integral representation is solved for the space, energy, direction and time variables by Monte Carlo methods. Adjoint particles are defined with properties in some respects contrary to those of neutrons. Adjoint particle histories are constructed from which estimates are obtained of the desired quantity. Adjoint cross sections are defined with which the nuclide and reaction type are selected in a collision. The energy after a collision is selected from adjoint energy distributions calculated together with the adjoint cross sections in advance of the actual Monte Carlo calculation. For multiplying systems successive generations of adjoint particles are obtained which will die out for subcritical systems with a fixed neutron source and will be kept approximately stationary for Eigen function problems. Completely arbitrary problems can

  8. Comparison of Standard Light Water Reactor Cross-Section Libraries using the United States Nuclear Regulatory Commission Boiling Water Reactor Benchmark Problem

    Directory of Open Access Journals (Sweden)

    Kulesza Joel A.

    2016-01-01

    Full Text Available This paper describes a comparison of contemporary and historical light water reactor shielding and pressure vessel dosimetry cross-section libraries for a boiling water reactor calculational benchmark problem. The calculational benchmark problem was developed at Brookhaven National Laboratory by the request of the U. S. Nuclear Regulatory Commission. The benchmark problem was originally evaluated by Brookhaven National Laboratory using the Oak Ridge National Laboratory discrete ordinates code DORT and the BUGLE-93 cross-section library. In this paper, the Westinghouse RAPTOR-M3G three-dimensional discrete ordinates code was used. A variety of cross-section libraries were used with RAPTOR-M3G including the BUGLE93, BUGLE-96, and BUGLE-B7 cross-section libraries developed at Oak Ridge National Laboratory and ALPAN-VII.0 developed at Westinghouse. In comparing the calculated fast reaction rates using the four aforementioned cross-section libraries in the pressure vessel capsule, for six dosimetry reaction rates, a maximum relative difference of 8% was observed. As such, it is concluded that the results calculated by RAPTOR-M3G are consistent with the benchmark and further that the different vintage BUGLE cross-section libraries investigated are largely self-consistent.

  9. Specification of the Advanced Burner Test Reactor Multi-Physics Coupling Demonstration Problem

    Energy Technology Data Exchange (ETDEWEB)

    Shemon, E. R. [Argonne National Lab. (ANL), Argonne, IL (United States); Grudzinski, J. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Lee, C. H. [Argonne National Lab. (ANL), Argonne, IL (United States); Thomas, J. W. [Argonne National Lab. (ANL), Argonne, IL (United States); Yu, Y. Q. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-12-21

    This document specifies the multi-physics nuclear reactor demonstration problem using the SHARP software package developed by NEAMS. The SHARP toolset simulates the key coupled physics phenomena inside a nuclear reactor. The PROTEUS neutronics code models the neutron transport within the system, the Nek5000 computational fluid dynamics code models the fluid flow and heat transfer, and the DIABLO structural mechanics code models structural and mechanical deformation. The three codes are coupled to the MOAB mesh framework which allows feedback from neutronics, fluid mechanics, and mechanical deformation in a compatible format.

  10. Problems specific to the piping of sodium-cooled fast breeder reactors

    International Nuclear Information System (INIS)

    Vrillon, B.; Befre, J.; Schaller, K.

    1975-01-01

    A certain number of specific problems arising in connection with the sodium pipes in fast neutron reactors, especially those of large diameter, are presented. The supporting system must be designed to achieve the best compromise among stresses due to weight and various stresses of thermal origin. Large-scale experimental studies carried out on actual elements of the intermediate circuit of the Phenix reactor showed that the circuits can withstand considerable deformation collapse of the walls without danger of leakage. Protection studies against earthquakes are mentionned [fr

  11. Iterative solution to the optimal control of depletion problem in pressurized water reactors

    International Nuclear Information System (INIS)

    Colletti, J.P.

    1981-01-01

    A method is described for determining the optimal time and spatial dependence of control absorbers in the core of a pressurized water reactor over a single refueling cycle. The reactor is modeled in two dimensions with many regions using two-group diffusion theory. The problem is formulated as an optimal control problem with the cycle length fixed and the initial reactor state known. Constraints are placed on the regionwise normalized powers, control absorber concentrations, and the critical soluble boron concentration of the core. The cost functional contains two terms which may be used individually or together. One term maximizes the end-of-cycle (EOC) critical soluble boron concentration, and the other minimizes the norm of the distance between the actual and a target EOC burnup distribution. Results are given for several test problems which are based on a three-region model of the Three Mile Island Unit 1 reactor. The resulting optimal control strategies are bang-bang and lead to EOC states with the power peaking at its maximum and no control absorbers remaining in the core. Throughout the cycle the core soluble boron concentration is zero

  12. An approach using quantum ant colony optimization applied to the problem of nuclear reactors reload

    International Nuclear Information System (INIS)

    Silva, Marcio H.; Lima, Alan M.M. de; Schirru, Roberto; Medeiros, J.A.C.C.

    2009-01-01

    The basic concept behind the nuclear reactor fuel reloading problem is to find a configuration of new and used fuel elements, to keep the plant working at full power by the largest possible duration, within the safety restrictions. The main restriction is the power peaking factor, which is the limit value for the preservation of the fuel assembly. The QACO A lfa algorithm is a modified version of Quantum Ant Colony Optimization (QACO) proposed by Wang et al, which uses a new actualization method and a pseudo evaporation step. We examined the QACO A lfa behavior associated to physics of reactors code RECNOD when applied to this problem. Although the QACO have been developed for continuous functions, the binary model used in this work allows applying it to discrete problems, such as the mentioned above. (author)

  13. An internally illuminated monolith reactor: Pros and cons relative to a slurry reactor

    NARCIS (Netherlands)

    Carneiro, Joana T.; Carneiro, J.T.; Berger, Rob; Moulijn, Jacob A.; Mul, Guido

    2009-01-01

    In the present study, kinetic models for the photo-oxidation of cyclohexane in two different photoreactor systems are discussed: a top illumination reactor (TIR) representative of a slurry reactor, and the so-called internally illuminated monolith reactor (IIMR) representing a reactor containing

  14. The International Science and Technology Center (ISTC) and ISTC projects related to research reactors. Information review

    International Nuclear Information System (INIS)

    Tocheniy, L.; Rudneva, V.Ya.

    1998-01-01

    1. ISTC - history, activities, outlook: The ISTC is an intergovernmental organization established by agreement between the Russian Federation, the European Union, Japan, and the United States. Since 1994, Finland, Sweden, Norway, Georgia, Armenia, Belarus, Kazakhstan and the Kyrgyz Republic have acceded to the Agreement and Statute. At present, the Republic of Korea is finishing the process of accession to the ISTC. All work of the ISTC is aimed at the goals defined in the ISTC Agreement: - To give CIS weapons scientists, particularly those who possess knowledge and skills related to weapons of mass destruction and their delivery systems, the opportunities to redirect their talents to peaceful activities; - To contribute to solving national and international technical problems; - To support the transition to market-based economies; - To support basic and applied research; - To help integrate CIS weapons scientists into the international scientific community. The projects may be funded both through governmental funds of the Funding Parties specified for the ISTC, and by organizations, nominated as Funding Partners of the ISTC. According to the ISTC Statute, approved by the appropriate national organizations, funds used within ISTC projects are exempt from CIS taxes. As of March 1998, more than 1500 proposals had been submitted to the Center, of which 541 were approved for funding, for a total value of approximately US dollars 165 million. The number of scientists and engineers participating in the projects is more than 17,000. 2. Projects Related to Research Reactors: There are about 20 funded and as yet non-funded projects related to various problems of research reactors. Many of them address safety issues. Information review of the results and plans of both ongoing projects and as yet non-funded proposals related to research reactors will be presented with the aim assisting international researchers to establish partnerships or collaboration with ISTC projects

  15. High temperature electrochemistry related to light water reactor corrosion

    International Nuclear Information System (INIS)

    Nagy, Gabor; Kerner, Zsolt; Balog, Janos; Schiller, Robert

    2004-01-01

    The present work deals with corrosion problems related to conditions which prevail in a WWER primary circuit. We had a two-fold aim: (A) electrochemical methods were applied to characterise the hydrothermally produced oxides of the cladding material (Zr-1%Nb) of nuclear fuel elements used in Russian made power reactors of WWER type, and (B) a number of possible reference electrodes were investigated with a view to high temperature applications. (A) Test specimens made of the cladding material, Zr-1%Nb, were immersed into an autoclave, filled with an aqueous solution typical to a WWER primary circuit, and were treated for different periods of time up to 28 weeks. The electrode potentials were measured and electrochemical impedance spectra (EIS) were taken regularly both as a function of oxidation time and temperature. This rendered information on the overall kinetics of oxide growth. By combining in situ and ex situ impedance measurements, with a particular view of the temperature dependence of EIS, we concluded that the high frequency region of impedance spectra is relevant to the presence of oxide layer on the alloy. This part of the spectra was treated in terms of a parallel CPE||R ox equivalent circuit (CPE denoting constant phase element, R ox ohmic resistor). The CPE element was understood as a dispersive resistance in terms of the continuous time random walk theory by Scher and Lax. This enabled us to tell apart electrical conductance and oxide growth with a model of charge transfer and recombination within the oxide layer as rate determining steps. (B) Three types of reference electrodes were tested within the framework of the LIRES EU5 project: (i) external Ag/AgCl, (ii) Pt/Ir alloy and (iii) Pd(Pt) double polarised active electrode. The most stable of the electrodes was found to be the Pt/Ir one. The Ag/AgCl electrode showed good stability after an initial period of some days, while substantial drifts were found for the Pd(Pt) electrode. EIS spectra of the

  16. Computer Use and Vision.Related Problems Among University ...

    African Journals Online (AJOL)

    Related Problems Among University Students In Ajman, United Arab Emirate. ... of 500 Students studying in Gulf Medical University, Ajman and Ajman University of ... prevalence of vision related problems was noted among university students.

  17. High-resolution coupled physics solvers for analysing fine-scale nuclear reactor design problems

    Science.gov (United States)

    Mahadevan, Vijay S.; Merzari, Elia; Tautges, Timothy; Jain, Rajeev; Obabko, Aleksandr; Smith, Michael; Fischer, Paul

    2014-01-01

    An integrated multi-physics simulation capability for the design and analysis of current and future nuclear reactor models is being investigated, to tightly couple neutron transport and thermal-hydraulics physics under the SHARP framework. Over several years, high-fidelity, validated mono-physics solvers with proven scalability on petascale architectures have been developed independently. Based on a unified component-based architecture, these existing codes can be coupled with a mesh-data backplane and a flexible coupling-strategy-based driver suite to produce a viable tool for analysts. The goal of the SHARP framework is to perform fully resolved coupled physics analysis of a reactor on heterogeneous geometry, in order to reduce the overall numerical uncertainty while leveraging available computational resources. The coupling methodology and software interfaces of the framework are presented, along with verification studies on two representative fast sodium-cooled reactor demonstration problems to prove the usability of the SHARP framework. PMID:24982250

  18. Perturbative methods for sensitivity calculation in safety problems of nuclear reactors: state-of-the-art

    International Nuclear Information System (INIS)

    Lima, Fernando R.A.; Lira, Carlos A.B.O.; Gandini, Augusto

    1995-01-01

    During the last two decades perturbative methods became an efficient tool to perform sensitivity analysis in nuclear reactor safety problems. In this paper, a comparative study taking into account perturbation formalisms (Diferential and Matricial Mthods and generalized Perturbation Theory - GPT) is considered. Then a few number of applications are described to analyze the sensitivity of some functions relavant to thermal hydraulics designs or safety analysis of nuclear reactor cores and steam generators. The behaviours of the nuclear reactor cores and steam generators are simulated, respectively, by the COBRA-IV-I and GEVAP codes. Results of sensitivity calculations have shown a good agreement when compared to those obtained directly by using the mentioned codes. So, a significative computational time safe can be obtained with perturbative methods performing sensitivity analysis in nuclear power plants. (author). 25 refs., 5 tabs

  19. Problems in manufacturing and transport of pressure vessels of integral reactors

    International Nuclear Information System (INIS)

    Kralovec, J.

    1997-01-01

    Integral water-cooled reactors are typical with eliminating large-diameter primary pipes and placing primary components, i.e. steam generators and pressurizers in reactor vessels. This arrangement leads to reactor pressure vessels of large dimensions: diameters, heights and thick walls and subsequently to great weights. Thus, even medium power units have pressure vessels which are on the very limit of present manufacturing capabilities. Principal manufacturing and inspection operations as well as pertinent equipment are concerned: welding, cladding, heat treatment, machining, shop-handling, non-destructive testing, hydraulic pressure tests etc. Tile transport of such a large and heavy component makes a problem which effects its design as well as the selection of the plant site. Railway, road and ship are possible ways of transport each of them having its advantages and limitations. Specific features and limits of the manufacture and transport of large pressure vessels are discussed in the paper. (author)

  20. Power Quality Problems Mitigation using Dynamic Voltage Restorer in Egypt Thermal Research Reactor (ETRR-2)

    International Nuclear Information System (INIS)

    Kandil, T.; Ayad, N.M.; Abdel Haleam, A.; Mahmoud, M.

    2013-01-01

    Egypt thermal research reactor (ETRR-2) was subjected to several Power Quality Problems such as voltage sags/swells, harmonics distortion, and short interruption. ETRR-2 encompasses a wide range of loads which are very sensitive to voltage variations and this leads to several unplanned shutdowns of the reactor due to trigger of the Reactor Protection System (RPS). The Dynamic Voltage Restorer (DVR) has recently been introduced to protect sensitive loads from voltage sags and other voltage disturbances. It is considered as one of the most efficient and effective solution. Its appeal includes smaller size and fast dynamic response to the disturbance. This paper describes a proposal of a DVR to improve power quality in ETRR-2 electrical distribution systems . The control of the compensation voltage is based on d-q-o algorithm. Simulation is carried out by Matlab/Simulink to verify the performance of the proposed method

  1. Advances in multiphase flow and related problems

    International Nuclear Information System (INIS)

    Papanicolaou, G.

    1986-01-01

    Proceedings of a workshop in multiphase flow held at Leesburg, Va. in June 1986 representing a cross-disciplinary approach to theoretical as well as computational problems in multiphase flow. Topics include composites, phase transitions, fluid-particle systems, and bubbly liquids

  2. Special Relativity as a Simple Geometry Problem

    Science.gov (United States)

    de Abreu, Rodrigo; Guerra, Vasco

    2009-01-01

    The null result of the Michelson-Morley experiment and the constancy of the one-way speed of light in the "rest system" are used to formulate a simple problem, to be solved by elementary geometry techniques using a pair of compasses and non-graduated rulers. The solution consists of a drawing allowing a direct visualization of all the fundamental…

  3. Extending the subspace hybrid method for eigenvalue problems in reactor physics calculation

    International Nuclear Information System (INIS)

    Zhang, Q.; Abdel-Khalik, H. S.

    2013-01-01

    This paper presents an innovative hybrid Monte-Carlo-Deterministic method denoted by the SUBSPACE method designed for improving the efficiency of hybrid methods for reactor analysis applications. The SUBSPACE method achieves its high computational efficiency by taking advantage of the existing correlations between desired responses. Recently, significant gains in computational efficiency have been demonstrated using this method for source driven problems. Within this work the mathematical theory behind the SUBSPACE method is introduced and extended to address core wide level k-eigenvalue problems. The method's efficiency is demonstrated based on a three-dimensional quarter-core problem, where responses are sought on the pin cell level. The SUBSPACE method is compared to the FW-CADIS method and is found to be more efficient for the utilized test problem because of the reason that the FW-CADIS method solves a forward eigenvalue problem and an adjoint fixed-source problem while the SUBSPACE method only solves an adjoint fixed-source problem. Based on the favorable results obtained here, we are confident that the applicability of Monte Carlo for large scale reactor analysis could be realized in the near future. (authors)

  4. Problems and legislative remedies of the parallel law systems in Japan for nuclear power reactors

    International Nuclear Information System (INIS)

    Irie, Kazutomo

    2011-01-01

    There are two established laws governing nuclear power reactors in Japan. One is the Electricity Utilities Industry Law, which regulates the nuclear power reactors, and the other is the so-called 'Reactor Regulation Law', which dually regulates the reactors in some phases. When a graded approach on the regulation of nuclear reactors was adopted, it extended over these two laws and was legislatively imperfect. Such imperfection created problems from the beginning. Also, the original regulatory structures presented by these laws had become obscure during the operation process of the graded regulation. The situation becomes further complicated by the revision of these laws in recent years. It appears that the trait of the regulatory procedural structure of the Electricity Utilities Industry Law has been weakened. As there is a pressing need to review the entire regulatory structure and to propose a unified regulatory system by combining these laws, this paper examines the merits and demerits of combining these laws under a unified regulation. (author)

  5. The initial value problem as it relates to numerical relativity.

    Science.gov (United States)

    Tichy, Wolfgang

    2017-02-01

    Spacetime is foliated by spatial hypersurfaces in the 3+1 split of general relativity. The initial value problem then consists of specifying initial data for all fields on one such a spatial hypersurface, such that the subsequent evolution forward in time is fully determined. On each hypersurface the 3-metric and extrinsic curvature describe the geometry. Together with matter fields such as fluid velocity, energy density and rest mass density, the 3-metric and extrinsic curvature then constitute the initial data. There is a lot of freedom in choosing such initial data. This freedom corresponds to the physical state of the system at the initial time. At the same time the initial data have to satisfy the Hamiltonian and momentum constraint equations of general relativity and can thus not be chosen completely freely. We discuss the conformal transverse traceless and conformal thin sandwich decompositions that are commonly used in the construction of constraint satisfying initial data. These decompositions allow us to specify certain free data that describe the physical nature of the system. The remaining metric fields are then determined by solving elliptic equations derived from the constraint equations. We describe initial data for single black holes and single neutron stars, and how we can use conformal decompositions to construct initial data for binaries made up of black holes or neutron stars. Orbiting binaries will emit gravitational radiation and thus lose energy. Since the emitted radiation tends to circularize the orbits over time, one can thus expect that the objects in a typical binary move on almost circular orbits with slowly shrinking radii. This leads us to the concept of quasi-equilibrium, which essentially assumes that time derivatives are negligible in corotating coordinates for binaries on almost circular orbits. We review how quasi-equilibrium assumptions can be used to make physically well motivated approximations that simplify the elliptic

  6. Statistical evaluation of design-error related nuclear reactor accidents

    International Nuclear Information System (INIS)

    Ott, K.O.; Marchaterre, J.F.

    1981-01-01

    In this paper, general methodology for the statistical evaluation of design-error related accidents is proposed that can be applied to a variety of systems that evolves during the development of large-scale technologies. The evaluation aims at an estimate of the combined ''residual'' frequency of yet unknown types of accidents ''lurking'' in a certain technological system. A special categorization in incidents and accidents is introduced to define the events that should be jointly analyzed. The resulting formalism is applied to the development of U.S. nuclear power reactor technology, considering serious accidents (category 2 events) that involved, in the accident progression, a particular design inadequacy. 9 refs

  7. Ethical Problems Related to Surrogate Motherhood

    OpenAIRE

    Erdem Aydin

    2006-01-01

    Being unable to have children is an important problem for married couples. At present, new reproduction techniques help these couples while those who can not find any solution try new approaches. One of these is the phenomenon of surrogate motherhood, which is based upon an agreement between the infertile couple and surrogate mother. Surrogate mother may conceive with the sperm of the male of the involved couple as well as by the transfer of the embryo formed by invitro fertilization. Couples...

  8. Ethical Problems Related to Surrogate Motherhood

    Directory of Open Access Journals (Sweden)

    Erdem Aydin

    2006-03-01

    Full Text Available Being unable to have children is an important problem for married couples. At present, new reproduction techniques help these couples while those who can not find any solution try new approaches. One of these is the phenomenon of surrogate motherhood, which is based upon an agreement between the infertile couple and surrogate mother. Surrogate mother may conceive with the sperm of the male of the involved couple as well as by the transfer of the embryo formed by invitro fertilization. Couples who choose to have a child born from a pregnancy or to whom they are genetically partially connected rather than adopting a child give rise to the emergence of some ethical problems. Traditional family notion based upon having children after the union of the reproductive cells of the mother and father do not receive the pheneomenon of surrogate mother favourably. Such practices are criticised as they are far from being natural and other ethical problems are faced in the implementation.

  9. Two problems relating to cosmic censorship

    Energy Technology Data Exchange (ETDEWEB)

    Needham, T.R.A.

    1986-01-01

    In the First Problem one unambiguous prediction of cosmic censorship is put to the test, namely that it should be impossible to destroy a black hole (i.e., eliminate its horizon) by injecting test particles into it. Several authors have treated this problem and have verified the prediction for various special cases. This author shows that if a general charged spinning particle (with parameters very much smaller than the respective hole parameters) is injected in an arbitrary manner into an extreme Kerr-Newman black hole, then cosmic censorship is upheld. He also considers the injection of particles with parameters that are not small compared with those of the hole, for which cosmic censorship is apparently violated. The Second Problem is an investigation of a conjecture by W. Israel. It states, in essence, that collapsing stars will generically form black holes even though naked singularities may also be produced. More precisely, he conjectures that if a trapped surface forms during a collapse then it can be extended toward the future into a spacelike 3-cylinder OMEGA whose sections are trapped surfaces having dimensions that remain bounded above and below.

  10. Reactors

    DEFF Research Database (Denmark)

    Shah, Vivek; Vaz Salles, Marcos António

    2018-01-01

    The requirements for OLTP database systems are becoming ever more demanding. Domains such as finance and computer games increasingly mandate that developers be able to encode complex application logic and control transaction latencies in in-memory databases. At the same time, infrastructure...... engineers in these domains need to experiment with and deploy OLTP database architectures that ensure application scalability and maximize resource utilization in modern machines. In this paper, we propose a relational actor programming model for in-memory databases as a novel, holistic approach towards......-level function calls. In contrast to classic transactional models, however, reactors allow developers to take advantage of intra-transaction parallelism and state encapsulation in their applications to reduce latency and improve locality. Moreover, reactors enable a new degree of flexibility in database...

  11. Safety problems of nuclear power plants with channel-type graphite boiling water reactors

    International Nuclear Information System (INIS)

    Emel'yanov, I.Ya.; Vasilevskij, V.P.; Volkov, V.P.; Gavrilov, P.A.; Kramerov, A.Ya.; Kuznetsov, S.P.; Kunegin, E.P.; Rybakov, N.Z.

    1977-01-01

    Construction of nuclear power plants in a highly populated region near large industrial centres necessitates to pay a special attention to their nuclear and radiation safety. Safety problems of nuclear reactor operation are discussed, in particular, they are: reliable stoppage of fission chain reaction at any emergency cases; reliable core cooling with failure of various equipment; emergency core cooling with breached pipes of a circulating circuit; and prevention of radioactive coolant release outside the nuclear power plant in amount exceeding the values adopted. Channel-type water boiling reactors incorporate specific features requiring a new approach to safety operation of a reactor and a nuclear power plant. These include primarily a rather large steam volume in the coolant circuit, large amount of accumulated heat, void reactivity coefficient. Channel-type reactors characterized by fair neutron balance and flexible fuel cycle, have a series of advantages alleviating the problem of ensuring their safety. The possibility of reliable control over the state of each channel allows to replace failed fuel elements by the new ones, when operating on-load, to increase the number of circulating loops and reduce the diameter of main pipelines, simplifies significantly the problem of channel emergency cooling and localization of a radioactive coolant release from a breached circuit. The concept of channel-type reactors is based on the solution of three main problems. First, plant safety should be assured in emergency switch off of separate units and, if possible, energy conditions should be maintained, this is of particular importance considering the increase in unit power. Second, the system of safety and emergency cooling should eliminate a great many failures of fuel elements in case of potential breaches of any tube in the circulating circuit. Finally, rugged boxes and localizing devices should be provided to exclude damage of structural elements of the nuclear power

  12. IAEA Activities in the Area of Fast Reactors and Related Fuels and Fuel Cycles

    International Nuclear Information System (INIS)

    Monti, S.; Basak, U.; Dyck, G.; Inozemtsev, V.; Toti, A.; Zeman, A.

    2013-01-01

    Summary: • The IAEA role to support fast reactors and associated fuel cycle development programmes; • Main IAEA activities on fast reactors and related fuel and fuel cycle technology; • Main IAEA deliverables on fast reactors and related fuel and fuel cycle technology

  13. Multi-Physics Demonstration Problem with the SHARP Reactor Simulation Toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Merzari, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Shemon, E. R. [Argonne National Lab. (ANL), Argonne, IL (United States); Yu, Y. Q. [Argonne National Lab. (ANL), Argonne, IL (United States); Thomas, J. W. [Argonne National Lab. (ANL), Argonne, IL (United States); Obabko, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Jain, Rajeev [Argonne National Lab. (ANL), Argonne, IL (United States); Mahadevan, Vijay [Argonne National Lab. (ANL), Argonne, IL (United States); Tautges, Timothy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Solberg, Jerome [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ferencz, Robert Mark [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Whitesides, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-12-21

    This report describes to employ SHARP to perform a first-of-a-kind analysis of the core radial expansion phenomenon in an SFR. This effort required significant advances in the framework Multi-Physics Demonstration Problem with the SHARP Reactor Simulation Toolkit used to drive the coupled simulations, manipulate the mesh in response to the deformation of the geometry, and generate the necessary modified mesh files. Furthermore, the model geometry is fairly complex, and consistent mesh generation for the three physics modules required significant effort. Fully-integrated simulations of a 7-assembly mini-core test problem have been performed, and the results are presented here. Physics models of a full-core model of the Advanced Burner Test Reactor have also been developed for each of the three physics modules. Standalone results of each of the three physics modules for the ABTR are presented here, which provides a demonstration of the feasibility of the fully-integrated simulation.

  14. Some particular problems put by operating experimental reactors; Quelques problemes particuliers poses par le fonctionnement des piles laboratoires

    Energy Technology Data Exchange (ETDEWEB)

    Candiotti, C; Mabeix, R; Uguen, R [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    On basis of a six years experience in operating research reactors, the authors explain, first, the difference in their utilization between these piles and another similar ones and, after, in consequence, they set off corresponding servitudes. These servitudes put very particular problems in operating itself, maintenance, modifications or additions on these apparatus. (author) [French] Les redacteurs se basant sur six annees d'experience dans l'exploitation de reacteurs de recherche, exposent tout d'abord les differences d'utilisation entre ces engins et d'autres appareils fonctionnellement similaires et font ressortir, par voie de consequence, les servitudes correspondantes. Ces servitudes posent des problemes tres particuliers dans les domaines de l'exploitation proprement dite, de l'entretien, des modifications ou adjonctions apportees a l'ensemble. (auteur)

  15. Some particular problems put by operating experimental reactors; Quelques problemes particuliers poses par le fonctionnement des piles laboratoires

    Energy Technology Data Exchange (ETDEWEB)

    Candiotti, C.; Mabeix, R.; Uguen, R. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    On basis of a six years experience in operating research reactors, the authors explain, first, the difference in their utilization between these piles and another similar ones and, after, in consequence, they set off corresponding servitudes. These servitudes put very particular problems in operating itself, maintenance, modifications or additions on these apparatus. (author) [French] Les redacteurs se basant sur six annees d'experience dans l'exploitation de reacteurs de recherche, exposent tout d'abord les differences d'utilisation entre ces engins et d'autres appareils fonctionnellement similaires et font ressortir, par voie de consequence, les servitudes correspondantes. Ces servitudes posent des problemes tres particuliers dans les domaines de l'exploitation proprement dite, de l'entretien, des modifications ou adjonctions apportees a l'ensemble. (auteur)

  16. Improvement in or relating to methods and apparatus for refuelling nuclear reactors

    International Nuclear Information System (INIS)

    Shumyakin, E.P.; Sabir-de-Ribas, K.I.; Druzhinsky, I.A.; Kondratiev, P.V.; Andreichikov, B.I.; Slepov, L.M.; Borisjuk, E.V.; Smirnov, A.M.

    1977-01-01

    This invention relates to improvements in the methods and in the apparatus used for refuelling liquid metal cooled fast reactors and in particular to systems for cooling the fuel assemblies as they are removed from the reactor. (UK)

  17. An analog computer method for solving flux distribution problems in multi region nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Radanovic, L; Bingulac, S; Lazarevic, B; Matausek, M [Boris Kidric Institute of Nuclear Sciences Vinca, Beograd (Yugoslavia)

    1963-04-15

    The paper describes a method developed for determining criticality conditions and plotting flux distribution curves in multi region nuclear reactors on a standard analog computer. The method, which is based on the one-dimensional two group treatment, avoids iterative procedures normally used for boundary value problems and is practically insensitive to errors in initial conditions. The amount of analog equipment required is reduced to a minimum and is independent of the number of core regions and reflectors. (author)

  18. Application of Raptor-M3G to reactor dosimetry problems on massively parallel architectures - 026

    International Nuclear Information System (INIS)

    Longoni, G.

    2010-01-01

    The solution of complex 3-D radiation transport problems requires significant resources both in terms of computation time and memory availability. Therefore, parallel algorithms and multi-processor architectures are required to solve efficiently large 3-D radiation transport problems. This paper presents the application of RAPTOR-M3G (Rapid Parallel Transport Of Radiation - Multiple 3D Geometries) to reactor dosimetry problems. RAPTOR-M3G is a newly developed parallel computer code designed to solve the discrete ordinates (SN) equations on multi-processor computer architectures. This paper presents the results for a reactor dosimetry problem using a 3-D model of a commercial 2-loop pressurized water reactor (PWR). The accuracy and performance of RAPTOR-M3G will be analyzed and the numerical results obtained from the calculation will be compared directly to measurements of the neutron field in the reactor cavity air gap. The parallel performance of RAPTOR-M3G on massively parallel architectures, where the number of computing nodes is in the order of hundreds, will be analyzed up to four hundred processors. The performance results will be presented based on two supercomputing architectures: the POPLE supercomputer operated by the Pittsburgh Supercomputing Center and the Westinghouse computer cluster. The Westinghouse computer cluster is equipped with a standard Ethernet network connection and an InfiniBand R interconnects capable of a bandwidth in excess of 20 GBit/sec. Therefore, the impact of the network architecture on RAPTOR-M3G performance will be analyzed as well. (authors)

  19. Problem of spent fuel storage from commercial nuclear reactors in USA

    International Nuclear Information System (INIS)

    Elagin, Yu.P.

    1996-01-01

    The problem on spent fuel storage in the USA is considered. According to the law and agreement, concluded with electrical companies, the USA should begin to receive the spent fuel from commercial reactors in 1998, however they are not ready for it. The consortium for constructing a centralized storage, financed from private sources for its temporary disposition is established recently. The spent fuel receipt is planned for 2002

  20. Current problems in Russian-Latvian relations

    Directory of Open Access Journals (Sweden)

    Mezhevich Nikolay

    2013-09-01

    Full Text Available Current relations between Russia and Latvia are still influenced by a series of mutual claims that appeared after the demise of the USSR. Latvia — as well as Estonia and Lithuania — is both an EU and NATO member state. However, unlike the above mentioned countries, its relations with Russia are developing at a more pragmatic level. Numerous political differences often result in economic losses both for Latvia and Russia. Despite the fact that Latvia has been an independent state for more than 20 years, there are still some unresolved issues in its relations with Russia. Today, relations between the two countries are often viewed through the prism of EU — Russia relations. Nonetheless, they often do not fit this context. Settling differences between Latvia and Russia will contribute to trade relations, which are increasingly important for both parties. In order to prevent and localise emerging conflicts, diplomats, politicians, and experts should interpret Russian-Latvian relations in view of the national features without referring to theoretical models based on the mythological “unity” of the three Baltic States.

  1. Management of research reactor; dynamic characteristics analysis for reactor structures related with vibration of HANARO fuel assembly

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Chang Kee; Shim, Joo Sup [Shinwa Technology Information, Seoul (Korea)

    2001-04-01

    The objective of this study is to deduce the dynamic correlation between the fuel assembly and the reactor structure. Dynamic characteristics analyses for reactor structure related with vibration of HANARO fuel assembly have been performed For the dynamic characteristic analysis, the in-air models of the round and hexagonal flow tubes, 18-element and 36-element fuel assemblies, and reactor structure were developed. By calculating the hydrodynamic mass and distributing it on the in-air models, the in-water models of the flow tubes, the fuel assemblies, and the reactor structure were developed. Then, modal analyses for developed in-air and in-water models have been performed. Especially, two 18-element fuel assemblies and three 36-element fuel assemblies were included in the in-water reactor models. For the verification of the modal analysis results, the natural frequencies and the mode shapes of the fuel assembly were compared with those obtained from the experiment. Finally the analysis results of the reactor structure were compared with them performed by AECL Based on the reactor model without PCS piping, the in-water reactor model including the fuel assemblies was developed, and its modal analysis was performed. The analysis results demonstrate that there are no resonance between the fuel assembly and the reactor structures. 26 refs., 419 figs., 85 tabs. (Author)

  2. The International Science and Technology Center (ISTC) and ISTC projects related to research reactors: information review

    Energy Technology Data Exchange (ETDEWEB)

    Tocheniy, L. V.; Rudneva, V. Ya. [ISTC, Moscow (Russian Federation)

    1998-07-01

    The ISTC is an intergovernmental organization established by agreement between the Russian Federation, the European Union, Japan, and the United States. Since 1994, Finland, Sweden, Norway, Georgia, Belarus, Kazakhstan and the Kyrgyz Republic have acceded to the Agreement and Statute. At present, the Republic of Korea is finishing the process of accession to the ISTC. All work of the ISTC is aimed at the goals defined in the ISTC Agreement: To give CIS weapons scientists, particularly those who possess knowledge and skills related to weapons of mass destruction and their delivery systems, the opportunities to redirect their talents to peaceful activities; To contribute to solving national and international technical problems; To support the transition to market-based economics; To support basic and applied research; To help integrate CIS weapons scientists into the international scientific community. The projects may be funded both through governmental funds of the Funding partners of the ISTC. According to the ISTC Statute, approved by the appropriate national organizations, funds used within ISTC projects are exempt from CIS taxes. As of March 1998, more than 1500 proposals had been submitted to the Center, of which 551 were approved for funding, for a total value of approximately US$166 million. The number of scientists and engineers participating in the projects is more than 18000. There are about 20 funded and as yet nonfunded projects related to various problems of research reactors. Many of them address safety issues. Information review of the results and plans of both ongoing projects and as yet nonfunded proposals related to research reactors will be presented with the aim assisting international researchers to establish partnerships or collaboration with ISTC projects. The following groups of ISTC projects will be represented: 1. complex computer simulator s for research reactors; 2. reactor facility decommissioning; 3. neutron sources for medicine; 4

  3. The Great Deluge Algorithm applied to a nuclear reactor core design optimization problem

    International Nuclear Information System (INIS)

    Sacco, Wagner F.; Oliveira, Cassiano R.E. de

    2005-01-01

    The Great Deluge Algorithm (GDA) is a local search algorithm introduced by Dueck. It is an analogy with a flood: the 'water level' rises continuously and the proposed solution must lie above the 'surface' in order to survive. The crucial parameter is the 'rain speed', which controls convergence of the algorithm similarly to Simulated Annealing's annealing schedule. This algorithm is applied to the reactor core design optimization problem, which consists in adjusting several reactor cell parameters, such as dimensions, enrichment and materials, in order to minimize the average peak-factor in a 3-enrichment-zone reactor, considering restrictions on the average thermal flux, criticality and sub-moderation. This problem was previously attacked by the canonical genetic algorithm (GA) and by a Niching Genetic Algorithm (NGA). NGAs were designed to force the genetic algorithm to maintain a heterogeneous population throughout the evolutionary process, avoiding the phenomenon known as genetic drift, where all the individuals converge to a single solution. The results obtained by the Great Deluge Algorithm are compared to those obtained by both algorithms mentioned above. The three algorithms are submitted to the same computational effort and GDA reaches the best results, showing its potential for other applications in the nuclear engineering field as, for instance, the nuclear core reload optimization problem. One of the great advantages of this algorithm over the GA is that it does not require special operators for discrete optimization. (author)

  4. Reactor siting risk comparisons related to recommendations of NUREG-0625

    International Nuclear Information System (INIS)

    Barsell, A.W.; Dombek, F.S.; Orvis, D.D.

    1980-11-01

    This document evaluates how implementing the remote siting recommendations for nuclear reactors (NUREG-0625) made by the Siting Policy Task Force of the US Nuclear Regulatory Commission (NRC) can reduce potential public risk. The document analyzes how population density affects site-specific risk for both light water reactors (LWRs) and high-temperature gas-cooled reactors

  5. Problems and Issues Related to Alternative Education.

    Science.gov (United States)

    Pilat, Mary

    1997-01-01

    Symposium participants identified policy issues in these areas related to alternative education for at-risk youth: choice, equity, public perception, definition, philosophy, stakeholder involvement, evaluation, staffing, curriculum, governance, and financing. Public discourse and policy discussion were considered essential to implementing…

  6. Relative Effects of Problem-Solving and Concept Mapping ...

    African Journals Online (AJOL)

    Relative Effects of Problem-Solving and Concept Mapping Instructional ... mapping strategies are also discussed and their significance and importance to students. ... development of problem solving skills before the end of SSCE Programmebr ...

  7. Child prostitution: magnitude and related problems.

    Science.gov (United States)

    Ayalew, T; Berhane, Y

    2000-07-01

    In Ethiopia, very little is known about prostitution in general and about child prostitution in particular. The objective of this study was to determine the magnitude of child prostitution and to identify problems associated with it. A cross-sectional study design was utilized. Data were collected using structured questionnaire. A total of 650 commercial sex workers were interviewed. Eighty eight (13.5%) were below the age of 18 years at the time of data collection. At the time of joining prostitution 268 (41.2%) were under 18 years of age. Poverty, disagreement with family, and peer influence were the major reasons leading to prostitution. Child prostitutes were likely to be victim of physical violence [OR = (95% C.I.) = 1.93(1.18,3.15)] and sexual violence [OR = (95% C.I.) = 2.20(1.36,3.35)] compared to adult prostitutes. Child prostitutes were about five times more likely to desire rejoining their family than the adult prostitutes [OR = (95% C.I) = 5.47(3.01;9.93)]. Strategies need to be developed to rescue child prostitutes from on-job violence, and to establish a rehabilitation program for those interested to discontinue prostitution along with efforts to minimize entry into prostitution.

  8. Particle Swarm Optimization applied to combinatorial problem aiming the fuel recharge problem solution in a nuclear reactor

    International Nuclear Information System (INIS)

    Meneses, Anderson Alvarenga de Moura; Schirru, Roberto

    2005-01-01

    This work focuses on the usage the Artificial Intelligence technique Particle Swarm Optimization (PSO) to optimize the fuel recharge at a nuclear reactor. This is a combinatorial problem, in which the search of the best feasible solution is done by minimizing a specific objective function. However, in this first moment it is possible to compare the fuel recharge problem with the Traveling Salesman Problem (TSP), since both of them are combinatorial, with one advantage: the evaluation of the TSP objective function is much more simple. Thus, the proposed methods have been applied to two TSPs: Oliver 30 and Rykel 48. In 1995, KENNEDY and EBERHART presented the PSO technique to optimize non-linear continued functions. Recently some PSO models for discrete search spaces have been developed for combinatorial optimization. Although all of them having different formulation from the ones presented here. In this paper, we use the PSO theory associated with to the Random Keys (RK)model, used in some optimizations with Genetic Algorithms. The Particle Swarm Optimization with Random Keys (PSORK) results from this association, which combines PSO and RK. The adaptations and changings in the PSO aim to allow the usage of the PSO at the nuclear fuel recharge. This work shows the PSORK being applied to the proposed combinatorial problem and the obtained results. (author)

  9. The potential for expert system support in solving the pressurized water reactor fuel shuffling problem

    International Nuclear Information System (INIS)

    Rothleder, B.M.; Poetschat, G.R.; Faught, W.S.; Eich, V.J.

    1988-01-01

    The fuel shuffling problem is posed by the need to reposition partially burned assemblies to achieve minimum X-Y pin power peaks reload cycles of pressurized water reactors. This problem is a classic artificial intelligence (AI) problem and is highly suitable for AI expert system solution assistance, in contrast to the conventional solution, which ultimately depends solely on trial and error. Such a fuel shuffling assistant would significantly reduce engineering and computer execution time for conventional loading patterns and, much more importantly, even more significantly for low-leakage loading patterns. A successful hardware/software demonstrator has been introduced, paving the way for development of a broadly expert system program. Such a program, upon incorporating the recently developed technique perverse depletion, would provide a directed path for solving the low-leakage problem

  10. Study and application of ANISN and DOT-II nuclear cores in reactor physics problems

    International Nuclear Information System (INIS)

    Dias, Artur Flavio

    1980-01-01

    To solve time-independent neutrons and/or gamma rays transport problems in nuclear reactors, two codes available at IPEN were studied and applied to solve benchmark problems. The ANISN code solves the one-dimensional Boltzmann transport equation for neutrons or gamma rays, in plane, spherical, or cylindrical geometries. The DOT-II code solves the same equation in two-dimensional space for plane, cylindrical and circular geometries. General anisotropic scattering allowed in both codes. Moreover, pointwise convergence criteria, and alternate step function difference equations are also used in order to remove the oscillating flux distributions, sometimes found in discrete ordinates solutions. Basic theories and numerical techniques used in these codes are studied and summarized. Benchmark problems have been solved using these codes. Comparisons of the results show that both codes can be used with confidence in the analysis of nuclear problems. (author)

  11. Issues related to the Fermion mass problem

    Science.gov (United States)

    Murakowski, Janusz Adam

    1998-09-01

    This thesis is divided into three parts. Each illustrates a different aspect of the fermion mass issue in elementary particle physics. In the first part, the possibility of chiral symmetry breaking in the presence of uniform magnetic and electric fields is investigated. The system is studied nonperturbatively with the use of basis functions compatible with the external field configuration, the parabolic cylinder functions. It is found that chiral symmetry, broken by a uniform magnetic field, is restored by electric field. Obtained result is nonperturbative in nature: even the tiniest deviation of the electric field from zero restores chiral symmetry. In the second part, heavy quarkonium systems are investigated. To study these systems, a phenomenological nonrelativistic model is built. Approximate solutions to this model are found with the use of a specially designed Pade approximation and by direct numerical integration of Schrodinger equation. The results are compared with experimental measurements of respective meson masses. Good agreement between theoretical calculations and experimental results is found. Advantages and shortcommings of the new approximation method are analysed. In the third part, an extension of the standard model of elementary particles is studied. The extension, called the aspon model, was originally introduced to cure the so called strong CP problem. In addition to fulfilling its original purpose, the aspon model modifies the couplings of the standard model quarks to the Z boson. As a result, the decay rates of the Z boson to quarks are altered. By using the recent precise measurements of the decay rates Z → bb and Z /to [/it c/=c], new constraints on the aspon model parameters are found.

  12. The metrological problems of irradiation embrittlement of reactor pressure vessel steel

    International Nuclear Information System (INIS)

    Vodenicharov, S.; Kamenova, Ts.

    1993-01-01

    Neutron irradiation of reactor pressure vessel steels increases the T k -values of transition temperature from ductile to brittle fracture. This effect is very important in emergency situations, when the water cooling injection in the reactor results in high thermal gradients. In such cases there is a risk from the appearance of a brittle fracture with catastrophic crack propagation speed at relatively low stresses. That is why the T k -value determination is very important for the safe operation of the reactor systems. Some advanced experimental methods for T k -testing and control have been discussed in the present article and the standards of different countries have been compared. The methods applying subsize specimens and welding-restored specimens have been reviewed. (author)

  13. Plant to reduce reactor scrams and ASSET related analysis

    Energy Technology Data Exchange (ETDEWEB)

    Piirto, A [Teollisuuden Voima Oy (Finland)

    1997-10-01

    The report of events at the plant follows established rules. Basically, three categories of reports exist: first, the reactor scram report, secondly, the operational disturbance report and thirdly, the special report. The last named category covers events defined by authorities. It concentrates on safety related events, for example on failures to follow the requirements stipulated in the plant`s Technical Specifications. In general, special events are nuclear safety on the plant, the safety of the plant personnel or overall, the radiation safety in the plant`s vicinity. In the TVO`s experience feedback activity the greatest emphasis is put on events at the TVO plant. The events on the same type of plants come second. Due to limited resources, somewhat less attention is paid to events on the other types of plants. However, the experience feedback should become wider in practice so that it would be a part of everyday life in nuclear power plant operation.

  14. Plant to reduce reactor scrams and ASSET related analysis

    International Nuclear Information System (INIS)

    Piirto, A.

    1997-01-01

    The report of events at the plant follows established rules. Basically, three categories of reports exist: first, the reactor scram report, secondly, the operational disturbance report and thirdly, the special report. The last named category covers events defined by authorities. It concentrates on safety related events, for example on failures to follow the requirements stipulated in the plant's Technical Specifications. In general, special events are nuclear safety on the plant, the safety of the plant personnel or overall, the radiation safety in the plant's vicinity. In the TVO's experience feedback activity the greatest emphasis is put on events at the TVO plant. The events on the same type of plants come second. Due to limited resources, somewhat less attention is paid to events on the other types of plants. However, the experience feedback should become wider in practice so that it would be a part of everyday life in nuclear power plant operation

  15. Status of research reactor utilization and other related activities

    International Nuclear Information System (INIS)

    Calix, V.S.

    2004-01-01

    The report covers two parts; the first is on the progress of the cooperative projects planned for 2002 under the FNCA and the other part on the activities related to the PRR1, Philippine Research Reactor. In the 2001 Workshop at Beijing, the Country agreed to participate in the three areas for collaboration. A brief reports on these three projects are included. The Country representatives during this 2002 Workshop will do a more detailed presentation on Radioisotope Production (TcG) and Neutron Activation Analysis projects. The second part of this report deals with the issues/concerns impeding the rehabilitation of PRR1. In January 2002, the Institute created the PRR1 Strategic Plan Committee to look deeply into these issues and concerns. The results of the Committee's work are discussed. (author)

  16. Wavelet and Spectral Analysis of Some Selected Problems in Reactor Diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Sunde, Carl

    2004-12-01

    Both spectral and wavelet analysis were successfully used in various diagnostic problems involving non-stationary core processes in nuclear power reactors. Three different problems were treated: two-phase flow identification, detector tube impacting and core-barrel vibrations. The first two problems are of non-stationary nature, whereas the last one is not. In the first problem, neutron radiographic and visible light images of four different vertical two-phase flow regimes, bubbly, slug, chum and annular flow, were analysed and classified with a neuro-wavelet algorithm. The algorithm consists of a wavelet part, using the 2-D discrete wavelet transform and of an artificial neural network. It classifies the different flow regimes with up to 99% efficiency. Detector tubes in a Boiling Water Reactor may execute vibrations and may also impact on nearby fuel-assemblies. Signals from in-core neutron detectors in Ringhals-1 were analysed, for detection of impacting, with both a classical spectral method and wavelet-based methods. The wavelet methods include both the discrete and the continuous 1-D wavelet transform. It was found that there is agreement between the different methods as well as with visual inspections made during the outage at the plant. However, the wavelet technique has the advantage that it does not require expert judgement for the interpretation of the analysis. In the last part two analytical calculations of the neutron noise, induced by shell-mode core-barrel vibrations, were carried out. The results are in good agreement with calculations from a numerical simulator. An out-of-phase behaviour between in-core and ex-core positions was found, which is in agreement with earlier measurements from the Pressurised Water Reactor Ringhals-3. The results from these calculations are planned to be used when diagnosing the shell-mode core-barrel vibrations in an operating plant.

  17. Wavelet and Spectral Analysis of Some Selected Problems in Reactor Diagnostics

    International Nuclear Information System (INIS)

    Sunde, Carl

    2004-12-01

    Both spectral and wavelet analysis were successfully used in various diagnostic problems involving non-stationary core processes in nuclear power reactors. Three different problems were treated: two-phase flow identification, detector tube impacting and core-barrel vibrations. The first two problems are of non-stationary nature, whereas the last one is not. In the first problem, neutron radiographic and visible light images of four different vertical two-phase flow regimes, bubbly, slug, chum and annular flow, were analysed and classified with a neuro-wavelet algorithm. The algorithm consists of a wavelet part, using the 2-D discrete wavelet transform and of an artificial neural network. It classifies the different flow regimes with up to 99% efficiency. Detector tubes in a Boiling Water Reactor may execute vibrations and may also impact on nearby fuel-assemblies. Signals from in-core neutron detectors in Ringhals-1 were analysed, for detection of impacting, with both a classical spectral method and wavelet-based methods. The wavelet methods include both the discrete and the continuous 1-D wavelet transform. It was found that there is agreement between the different methods as well as with visual inspections made during the outage at the plant. However, the wavelet technique has the advantage that it does not require expert judgement for the interpretation of the analysis. In the last part two analytical calculations of the neutron noise, induced by shell-mode core-barrel vibrations, were carried out. The results are in good agreement with calculations from a numerical simulator. An out-of-phase behaviour between in-core and ex-core positions was found, which is in agreement with earlier measurements from the Pressurised Water Reactor Ringhals-3. The results from these calculations are planned to be used when diagnosing the shell-mode core-barrel vibrations in an operating plant

  18. Environmental protection problems from the standpoint of regeneration of fast neutron reactor fuel

    International Nuclear Information System (INIS)

    Gedeonov, L.I.; Lazarev, L.N.; Suprunenko, A.N.

    The discussion of the problem of environmental protection is based on two principles: a strict observance of legislatively established standards for permissible concentrations of radionuclides in objects of the environment and for dose loads for the population; all possible steps to reduce the contamination to a level justified in practice. Environmental protection steps are considered from the points of view of a systematic analysis. A survey of the environmental protection system near sources of radioactive discharges is given. The basic interactions and feedbacks are indicated. Characteristics differentiating the discharges of the fuel cycle of fast neutron breeder reactors from discharges of the slow neutron cycle are discussed. It is shown that it is necessary to study the overall regional and global interactions of discharges of the atomic power industry. The characteristics of situations at nuclear fuel cycle facilities of fast neutron reactors are discussed. The necessity of additional technical steps to prevent accidents and eliminate their effects if they take place is emphasized

  19. Related activities on management of ageing of Dalat Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lam, Pham Van [Reactor Dept., Nuclear Research Institute, Dalat (Viet Nam)

    1998-10-01

    The Dalat Nuclear Research Reactor (DNRR) is a pool type research reactor which was reconstructed in 1982 from the previous 250 kW TRIGA-MARK II reactor. The reactor core, the control and instrumentation system, the primary and secondary cooling systems as well as other associated systems were newly designed and installed. The renovated reactor reached its initial criticality in November 1983 and attained its nominal power of 500 kW in February 1984. Since then DNRR has been operated safely. Retained structures of the former reactor such as the reactor aluminum tank, the graphite reflector, the thermal column, the horizontal beam tubes and the radiation concrete shielding are 35 years old. During the recent years, in-service inspection has been carried out, the reactor control and instrumentation system were renovated due to ageing and obsolescence of its components, reactor general inspection and refurbishment were performed. Efforts are being made to cope with ageing of old reactor components to maintain safe operation of the DNRR. (author)

  20. Proceedings of first SWCR-KURRI academic seminar on research reactors and related research topics

    International Nuclear Information System (INIS)

    Kimura, Itsuro; Cong, Zhebao

    1986-01-01

    These are the proceedings of an academic seminar on research reactors and related research topics held at the Southwest Centre for Reactor Engineering Research and Design in Chengdu, Sichuan, People's Republic of China in September 24-26 in 1985. Included are the chairmen's addresses and 10 papers presented at the seminar in English. The titles of these papers are: (1) Nuclear Safety and Safeguards, (2) General Review of Thorium Research in Japanese Universities, (3) Comprehensive Utilization and Economic Analysis of the High Flux Engineering Test Reactor, (4) Present States of Applied Health Physics in Japan, (5) Neutron Radiography with Kyoto University Reactor, (6) Topics of Experimental Works with Kyoto University Reactor, (7) Integral Check of Nuclear Data for Reactor Structural Materials, (8) The Reactor Core, Physical Experiments and the Operation Safety Regulation of the Zero Energy Thermal Reactor for PWR Nuclear Power Plant, (9) HFETR Core Physical Parameters at Power, (10) Physical Consideration for Loads of Operated Ten Cycles in HFETR. (author)

  1. Alcohol-Related Problems And High Risk Sexual Behaviour In ...

    African Journals Online (AJOL)

    There was a significant association between alcohol-related problems and risky sexual behavior. Alcohol-related problems are fairly common in people already infected with HIV/AIDS and are associated with high-risk sexual behavior. Thus, screening and treatment should be part of an effective HIV intervention program.

  2. The criticality problem in reflected slab type reactor in the two-group transport theory

    International Nuclear Information System (INIS)

    Garcia, R.D.M.

    1978-01-01

    The criticality problem in reflected slab type reactor is solved for the first time in the two group neutron transport theory, by singular eingenfunctions expansion, the singular integrals obtained through continuity conditions of angular distributions at the interface are regularized by a recently proposed method. The result is a coupled system of regular integral equations for the expansion coefficients, this system is solved by an ordinary interactive method. Numerical results that can be utilized as a comparative standard for aproximation methods, are presented [pt

  3. Application of a numerical Laplace transform inversion technique to a problem in reactor dynamics

    International Nuclear Information System (INIS)

    Ganapol, B.D.; Sumini, M.

    1990-01-01

    A newly developed numerical technique for the Laplace transform inversion is applied to a classical time-dependent problem of reactor physics. The dynamic behaviour of a multiplying system has been analyzed through a continuous slowing down model, taking into account a finite slowing down time, the presence of several groups of neutron precursors and simplifying the spatial analysis using the space asymptotic approximation. The results presented, show complete agreement with analytical ones previously obtained and allow a deeper understanding of the model features. (author)

  4. Study on sociological approach to resolve maintenance related social problems

    International Nuclear Information System (INIS)

    Aoki, Takayuki

    2007-01-01

    This study proposes a sociological approach to resolve maintenance related social problems. As a result of consideration, the followings were found. (1) In general, solutions to some kinds of questions can be deduced from basic laws using some theories or methodologies in the field of the natural science or engineering. The approach to resolve maintenance related social problems is similar to the approach in the natural science or engineering. (2) The points of view based on fundamental human rights, market principles and community principles, and so on, are very important in resolving maintenance related social problems and can be placed as theories or tools for resolution. (3) If such theories or tools for resolving maintenance related social problems as described above are systematically prepared, it is estimated that it becomes very much easier to resolve maintenance related social problems. (author)

  5. Validation of the AZTRAN 1.1 code with problems Benchmark of LWR reactors

    International Nuclear Information System (INIS)

    Vallejo Q, J. A.; Bastida O, G. E.; Francois L, J. L.; Xolocostli M, J. V.; Gomez T, A. M.

    2016-09-01

    The AZTRAN module is a computational program that is part of the AZTLAN platform (Mexican modeling platform for the analysis and design of nuclear reactors) and that solves the neutron transport equation in 3-dimensional using the discrete ordinates method S_N, steady state and Cartesian geometry. As part of the activities of Working Group 4 (users group) of the AZTLAN project, this work validates the AZTRAN code using the 2002 Yamamoto Benchmark for LWR reactors. For comparison, the commercial code CASMO-4 and the free code Serpent-2 are used; in addition, the results are compared with the data obtained from an article of the PHYSOR 2002 conference. The Benchmark consists of a fuel pin, two UO_2 cells and two other of MOX cells; there is a problem of each cell for each type of reactor PWR and BWR. Although the AZTRAN code is at an early stage of development, the results obtained are encouraging and close to those reported with other internationally accepted codes and methodologies. (Author)

  6. Features of the Numerical Solution of Thermal Destruction Fuel Pins Problems in the Fast Reactor

    Science.gov (United States)

    Usov, E. V.; Butov, A. A.; Klimonov, I. A.; Chuhno, V. I.; Nikolaenko, A. V.; Zhdanov, V. S.; Pribaturin, N. A.; Strizhov, V. F.

    2017-11-01

    In this paper the description of the basic equations which can be used for calculation of melting of fuel and cladding of the fast reactor, moving of the melt on a fuel pin surface and its solidification is presented. The special attention is given speed of calculation algorithms and fidelity of the phenomena which are observed at a stage of severe accidents in fast reactors. For check of working capacity of initial models, numerical calculations of Stefan-type problems on front movement of melting/solidification in cylindrical geometry are presented. Comparison with the solutions received by known analytical methods is executed. For validation of the numerical realization of calculation algorithms the analysis is carried out and experiments in which melting of the model fuel pins of fast reactors was studied are chosen. On the basis of the chosen experiments calculation schemes taking into account initial and boundary conditions are prepared and modeling is performed. Modeling results are shown in the present paper. Estimation of calculation error of the basic physical parameters is done by results of the modeling and conclusions are drawn on a correctness of algorithms operation.

  7. Design and analysis of concrete reactor vessels: New developments, problems and trends

    International Nuclear Information System (INIS)

    Bazant, Z.P.

    1984-01-01

    This lecture reviews new developments in analysis and design of prestressed concrete reactor vessels (PCRV). After a brief assessment of the current status and experience, the advantages, disadvantages, and especially the safety features of PCRV, are discussed. Attention is then focused on the design of penetrations and openings, and on the design for high-temperature resistance - areas in which further developments are needed. Various possible designs for high-temperature exposure of concrete in a hypothetical accident are analyzed. Considered are not only PCRVs for gas-cooled reactors (GCR), but also guard vessels for liquid metal fast breeder reactors (LMFBR), for which designs mitigating the adverse effects of molten sodium, molten steel, and core melt are surveyed. Realistic analysis of the problems requires further development in the knowledge of material behavior and its mathematical modeling. Recent advances in the modeling of high-temperature response of concrete, including pore water transfer, pore pressure, creep and shrinkage are outlined. This is followed by a discussion of new developments in the analysis of cracking of concrete, where the need of switching from stress criteria to energy criteria for fracture is emphasized. The lecture concludes with a brief discussion of long-time behavior, the effect of aging, and probabilistic analysis of creep. (orig.)

  8. Summary of the progress of reactor physics in Japan reviewing the activities related to NEA Committee on Reactor Physics

    International Nuclear Information System (INIS)

    Hirota, Jitsuya

    1984-09-01

    The progress of fast and thermal reactor physics, fusion neutronics and shielding researches in these twenty years can be clearly recognized in the reviews of reactor physics activities in Japan which had been perpared by the Special Committee on Reactor Physics: the joint committee under Atomic Energy Society of Japan and JAERI. Many topics of those discussed at the NEACRP meetings concerned fast reactor physics. Information exchange on the topics such as adjustment of group cross sections by integral data, central worth discrepancy, sodium void effect and heterogeneous core stimulated the researches in Japan. And achievements in Japan including those in the JAERI Fast Critical Facility FCA were reported and contributed largely to the international co-operation. In addition, the contribution from Japan was also made concerning a study of fusion blanket. Among various specialists' meetings recommended by NEACRP, those on nuclear data and benchmarks for reactor shielding were often held since 1973 and helpful to the progress of shielding researches in Japan. The Third Specialists' Meeting on Reactor Noise (SMORN-III) was held in Tokyo in 1981, indicating the recent progress in safety-related applications of reactor noise analysis. The NEACRP benchmark tests were quite useful to the progress of reactor physics in Japan, which included the benchmark calculations of BWR lattice cell, key parameters and burn-up characteristics of a large LMFBR, FBR and PWR shielding, and so on. It may be noted that the benchmark test on reactor noise analysis methods was successfully conducted by Japan in connection with SMORN-III. In addition, the co-operation was positively made to the compilation of light water lattice data, and the preparation of reviews on actinide production and burn-up, and blanket physics. (J.P.N.)

  9. Some stress-related issues in tokamak fusion reactor first walls

    International Nuclear Information System (INIS)

    Majumdar, S.; Pai, B.; Ryder, R.H.

    1987-01-01

    Recent design studies of a tokamak fusion power reactor and of various blankets have envisioned surface heat fluxes on the first wall ranging from 0.1 to 1.0 MW/m 2 , and end-of-life irradiation fluences ranging from 100 dpa for the austenitic stainless steels to as high as 250 dpa for postulated vanadium alloys. Some tokamak blankets, particularly those using helium or liquid metal as coolant/breeder, may have to operate at relatively high coolant pressures so that the first wall may be subjected to high primary stress in addition to high secondary stresses such as thermal stresses or stresses due to constrained swelling. The present paper focusses on the various problems that may arise in the first wall because of stress and high neutron fluence, and discusses some of the design solutions that have been proposed to overcome these problems

  10. Problem statement: international safeguards for a light-water reactor fuels reprocessing plant

    International Nuclear Information System (INIS)

    Shipley, J.P.; Hakkila, E.A.; Dietz, R.J.; Cameron, C.P.; Bleck, M.E.; Darby, J.L.

    1979-03-01

    This report considers the problem of developing international safeguards for a light-water reactor (LWR) fuel reprocessing/conversion facility that combines the Purex process with conversion of plutonium nitrate to the oxide by means of plutonium (III) oxalate precipitation and calcination. Current international safeguards systems are based on the complementary concepts of materials accounting and containment and surveillance, which are designed to detect covert, national diversion of nuclear material. This report discusses the possible diversion threats and some types of countermeasures, and it represents the first stage in providing integrated international safeguards system concepts that make optimum use of available resources. The development of design methodology to address this problem will constitute a significant portion of the subsequent effort. Additionally, future technology development requirements are identified. 8 figures, 1 table

  11. The intermittent contact impact problem in piping systems of nuclear reactor

    International Nuclear Information System (INIS)

    Martin, A.; Ricard, A.; Millard, A.

    1981-09-01

    The intermittent contact problem is important in many pipe whip studies, specially as to the safety of nuclear reactors. The impact concept adopted is that of instantaneous impact, so that at the time of impact the two impacting structures instantaneously acquire the same velocity in the impact direction. Energy is dissipated by some mechanism whose spatial and temporal scale is small compared to these scales in the discrete model. This dissipation is associated with local plastic deformation. Different solutions are presented for solving this problem. The first one is a generalization of the modal superposition method, when the nonlinearities of the structure are only due to impact between structural components; the other ones are included in a step by step time history and can take in account geometrical non linearities and of behavior. Some industrial applications in nuclear technology are presented

  12. Efficient algorithms for flow simulation related to nuclear reactor safety

    International Nuclear Information System (INIS)

    Gornak, Tatiana

    2013-01-01

    Safety analysis is of ultimate importance for operating Nuclear Power Plants (NPP). The overall modeling and simulation of physical and chemical processes occuring in the course of an accident is an interdisciplinary problem and has origins in fluid dynamics, numerical analysis, reactor technology and computer programming. The aim of the study is therefore to create the foundations of a multi-dimensional non-isothermal fluid model for a NPP containment and software tool based on it. The numerical simulations allow to analyze and predict the behavior of NPP systems under different working and accident conditions, and to develop proper action plans for minimizing the risks of accidents, and/or minimizing the consequences of possible accidents. A very large number of scenarios have to be simulated, and at the same time acceptable accuracy for the critical parameters, such as radioactive pollution, temperature, etc., have to be achieved. The existing software tools are either too slow, or not accurate enough. This thesis deals with developing customized algorithm and software tools for simulation of isothermal and non-isothermal flows in a containment pool of NPP. Requirements to such a software are formulated, and proper algorithms are presented. The goal of the work is to achieve a balance between accuracy and speed of calculation, and to develop customized algorithm for this special case. Different discretization and solution approaches are studied and those which correspond best to the formulated goal are selected, adjusted, and when possible, analysed. Fast directional splitting algorithm for Navier-Stokes equations in complicated geometries, in presence of solid and porous obstacles, is in the core of the algorithm. Developing suitable pre-processor and customized domain decomposition algorithms are essential part of the overall algorithm amd software. Results from numerical simulations in test geometries and in real geometries are presented and discussed.

  13. Reactor

    International Nuclear Information System (INIS)

    Toyama, Masahiro; Kasai, Shigeo.

    1978-01-01

    Purpose: To provide a lmfbr type reactor wherein effusion of coolants through a loop contact portion is reduced even when fuel assemblies float up, and misloading of reactor core constituting elements is prevented thereby improving the reactor safety. Constitution: The reactor core constituents are secured in the reactor by utilizing the differential pressure between the high-pressure cooling chamber and low-pressure cooling chamber. A resistance port is formed at the upper part of a connecting pipe, and which is connect the low-pressure cooling chamber and the lower surface of the reactor core constituent. This resistance part is formed such that the internal sectional area of the connecting pipe is made larger stepwise toward the upper part, and the cylinder is formed larger so that it profiles the inner surface of the connecting pipe. (Aizawa, K.)

  14. Research reactor utilization. Summary reports of three study group meetings: Irradiation techniques at research reactors, held in Istanbul 15-19 November 1965; Research reactor operation and maintenance problems, held in Caracas 6-10 December 1965; and Research reactor utilization in the Far East, held in Lucas Heights 28 February - 4 March 1966

    International Nuclear Information System (INIS)

    1967-01-01

    The three sections of this book, which are summary reports of three Study Group meetings of the IAEA: Irradiation techniques at research reactors, Istanbul, 15-19 November 1965; Research reactor operation and maintenance problems, Caracas, 6-10 December 1965; and Research reactor utilization in the Far East, Lucas Heights, Australia, 28 February - 4 March 1966. These meetings were the latest in a series designed to promote efficient utilization of research reactors, to disseminate information on advances in techniques, to discuss common problems in reactor operations, and to outline some advanced areas of reactor-based research. (author)

  15. A Singular Perturbation Problem for Steady State Conversion of Methane Oxidation in Reverse Flow Reactor

    Directory of Open Access Journals (Sweden)

    Aang Nuryaman

    2012-11-01

    Full Text Available The governing equations describing the methane oxidation process in reverse flow reactor are given by a set of convective-diffusion equations with a nonlinear reaction term, where temperature and methane conversion are dependent variables. In this study, the process is assumed to be one-dimensional pseudo homogeneous model and takes place with a certain reaction rate in which the whole process of reactor is still workable. Thus, the reaction rate can proceed at a fixed temperature. Under this condition, we restrict ourselves to solve the equations for the conversion only. From the available data, it turns out that the ratio of the diffusion term to the reaction term is small. Hence, this ratio is considered as small parameter in our model and this leads to a singular perturbation problem. In the vicinity of small parameter in front of higher order term, the numerical difficulties will be found. Here, we present an analytical solution by means of matched asymptotic expansions. Result shows that, up to and including the first order of approximation, the solution is in agreement with the exact and numerical solutions of the boundary value problem.

  16. Assessment and mitigation of power quality problems for PUSPATI TRIGA Reactor (RTP)

    Science.gov (United States)

    Zakaria, Mohd Fazli; Ramachandaramurthy, Vigna K.

    2017-01-01

    An electrical power systems are exposed to different types of power quality disturbances. Investigation and monitoring of power quality are necessary to maintain accurate operation of sensitive equipment especially for nuclear installations. This paper will discuss the power quality problems observed at the electrical sources of PUSPATI TRIGA Reactor (RTP). Assessment of power quality requires the identification of any anomalous behavior on a power system, which adversely affects the normal operation of electrical or electronic equipment. A power quality assessment involves gathering data resources; analyzing the data (with reference to power quality standards) then, if problems exist, recommendation of mitigation techniques must be considered. Field power quality data is collected by power quality recorder and analyzed with reference to power quality standards. Normally the electrical power is supplied to the RTP via two sources in order to keep a good reliability where each of them is designed to carry the full load. The assessment of power quality during reactor operation was performed for both electrical sources. There were several disturbances such as voltage harmonics and flicker that exceeded the thresholds. To reduce these disturbances, mitigation techniques have been proposed, such as to install passive harmonic filters to reduce harmonic distortion, dynamic voltage restorer (DVR) to reduce voltage disturbances and isolate all sensitive and critical loads.

  17. Adjoint-based global variance reduction approach for reactor analysis problems

    International Nuclear Information System (INIS)

    Zhang, Qiong; Abdel-Khalik, Hany S.

    2011-01-01

    A new variant of a hybrid Monte Carlo-Deterministic approach for simulating particle transport problems is presented and compared to the SCALE FW-CADIS approach. The new approach, denoted by the Subspace approach, optimizes the selection of the weight windows for reactor analysis problems where detailed properties of all fuel assemblies are required everywhere in the reactor core. Like the FW-CADIS approach, the Subspace approach utilizes importance maps obtained from deterministic adjoint models to derive automatic weight-window biasing. In contrast to FW-CADIS, the Subspace approach identifies the correlations between weight window maps to minimize the computational time required for global variance reduction, i.e., when the solution is required everywhere in the phase space. The correlations are employed to reduce the number of maps required to achieve the same level of variance reduction that would be obtained with single-response maps. Numerical experiments, serving as proof of principle, are presented to compare the Subspace and FW-CADIS approaches in terms of the global reduction in standard deviation. (author)

  18. Reactor

    International Nuclear Information System (INIS)

    Ikeda, Masaomi; Kashimura, Kazuo; Inoue, Kazuyuki; Nishioka, Kazuya.

    1979-01-01

    Purpose: To facilitate the construction of a reactor containment building, whereby the inspections of the outer wall of a reactor container after the completion of the construction of the reactor building can be easily carried out. Constitution: In a reactor accommodated in a container encircled by a building wall, a space is provided between the container and the building wall encircling the container, and a metal wall is provided in the space so that it is fitted in the building wall in an attachable or detatchable manner. (Aizawa, K.)

  19. Measurements at the RA Reactor related to the VISA-2 project - Part 1, Start-up of the RA reactor and measurement of new RA reactor core parameters

    International Nuclear Information System (INIS)

    Markovic, H.

    1962-07-01

    The objective of the measurements was determining the neutron flux in the RA reactor core. Since the number of fuel channels is increased from 56 to 68 within the VISA-2 project, it was necessary to attain criticality of the RA reactor and measure the neutron flux properties. The 'program of RA reactor start-up' has been prepared separately and it is included in this report. Measurements were divided in two phases. First phase was measuring of the neutron flux after the criticality was achieved but at zero power. During phase two measurements were repeated at several power levels, at equilibrium xenon poisoning. This report includes experimental data of flux distributions and absolute values of the thermal and fast neutron flux in the RA reactor experimental channels and values of cadmium ratio for determining the neutron epithermal flux. Data related to calibration of regulatory rods for cold un poisoned core are included [sr

  20. Status review of large fast reactor core designs and their dynamics related features

    International Nuclear Information System (INIS)

    Spenke, H.; Kiefhaber, E.

    1982-01-01

    Since several years conventional and unconventional concepts of large fast reactor cores have been investigated in the Federal Republic of Germany at INTERATOM and Kernforschungszentrum Karlsruhe. The work was performed jointly with Belgonucleaire (Belgium). Basically, the studies were aimed at the determination of the performance potential of different core concepts for large fast reactors. Thus the following points were considered: power distribution, neutron fluence and residence time, doubling time, uranium ore consumption, dynamics and safety related features, economics, cooling strategy, core element bowing behaviour. In this paper, the state of the analysis will be presented with emphasis on those points relevant for this meeting. However, we have to make clear, that dynamic and accident studies are still under way and that we are not yet able to cover these aspects in a quantitative manner. This is due to the fact, that the efforts in the DeBeNe-countries have been concentrated on the work necessary for being granted the different licenses for SNR 300, fast breeder prototype reactor near Kalkar. As we expect to obtain these important licenses at the beginning of 1982, an increased man power can be devoted to studies of dynamic and safety problems of large fast cores from that time on. These studies have to fit into the planning recently announced by the utility ESK who will be ordering SNR 2, the first demonstration breeder reactor of Germany, Belgium, Netherlands and France. The planning calls for concept decisions in 1983, leading to an engineering contract for SNR 2 in 1983/1984. Accordingly we shall have to complete and evaluate the ongoing core concept Investigations till 1983 resulting in a subsequent final choice

  1. Proceedings of the Workshop on Experimental and theoretical problems around actinides for future reactors

    International Nuclear Information System (INIS)

    Kerveno, Maelle; Dupuis, Marc; Bauge, E.; Hilaire, S.; Romain, P.; Morillon, B.; Delaroche, J.P.; Dupuis, M.; Peru, S.; Belier, G.; Bonnet, T.; Laborie, J.M.; Laurent, B.; Ledoux, X.; Varignon, C.; Meot, V.; Bernard, David; Capote, Roberto; Kawano, T.; Bond, E.; Vieira, D.J.; Wilhelmy, J.B.; Raynal, J.; Plompen, Arjan J.M.; Drohe, J.C.; Nankov, N.; Nyman, M.; Rouki, C.; Bacquias, A.; Dessagne, Ph.; Henning, G.; Karam, H.; Kerveno, M.; Rudolf, G.; Thiry, J.C.; Borcea, C.; Negret, A.; Stanoiu, M.; Bucurescu, D.; Deleanu, D.; Filipescu, D.; Ghita, D.; Glodariu, T.; Marginean, N.; Marginean, R.; Mihai, C.; Olacel, A.; Pascu, S.; Sava, T.; Stroe, L.; Goriely, S.; Pavlik, A.; Jericha, E.; Ledoux, X.; Becker, J.A.; Macri, R.; Authier, N.; Hyneck, D.; Jansen, Y.; Legendre, J.; Jacquet, X.; Gunsing, Frank; Henning, Greg

    2014-03-01

    Since the two last decades, in the framework of general researches on future reactors, strong efforts have been devoted to improve the quantity and quality of nuclear data. Indeed, in order to improve safety margins and fuel optimization, but also to develop new kind of reactors or fuel cycles, accurate nuclear data are mandatory. At the end of the twentieth century, nuclear data bases did not reach the required quality level to be used in future reactor simulations. Therefore, both experimentalists and theoreticians, in the framework of several European research programs (HINDAS, NUDATRA, ANDES, CHANDA...), have tried to make the situation better. New sets of precise data measurements concerning fission, capture, (n,xn),..., reaction cross sections for a large variety of nuclei have been initiated. From evaluation point of view, the JEFF project has also improved the quality of nuclear data bases for several nuclei. In parallel, on the theoretical side, progress has also been made concerning cross section modeling in a wide range of energy (eV to GeV). The goal was to provide theoretical models with a good predictive power to feed data bases where experimental data are still missing and where the measurement is too complex. In this context, for example, a new nuclear reaction code TALYS has been developed. Collaboration between experimentalists, theoreticians and evaluators are then of strong interest to make progress. The number of problems to be solved covers various fields of nuclear reactions such as fission, capture or inelastic scattering. In order to avoid too large an audience we have decided, as a first step, to focus on inelastic scattering on actinides. Experimentally, three main methods exist to measure the total inelastic cross section: activation, detection of the emitted neutrons and prompt-gamma spectroscopy. This last method is, nevertheless, dependent on theoretical models since it provides (n,xn γ) cross sections and not the total inelastic

  2. Swedish Work on Brittle-Fracture Problems in Nuclear Reactor Pressure Vessels

    International Nuclear Information System (INIS)

    Grounes, M.

    1966-03-01

    After a short review of the part of the Swedish nuclear energy program that is of interest in this context the Swedish reactor pressure vessels and the reasoning behind the choice of materials are surveyed. Problems and desirable aims for future reactors are discussed. Much work is now being done on new types of pressure vessel steels with high strength, low transition temperature and good corrosion resistance. These steels are of the martensitic austenitic type Bofors 2RMO (13 % Cr, 6 % Ni, 1. 5 % Mo) and of the ferritic martensitic austenitic type Avesta 248 SV (16 % Cr, 5 % Ni, 1 % Mo). An applied philosophy for estimating the brittle-fracture tendency of pressure vessels is described. As a criterion of this tendency we use the crack-propagation transition temperature, e. g. as measured by the Robertson isothermal crack-arrest test. An estimate of this transition temperature at the end of the reactor' s lifetime must take increases due to fabrication, welding, geometry, ageing and irradiation into account. The transition temperature vs. stress curve moves towards higher temperatures during the reactor' s lifetime. As long as this curve does not cross the reactor vessel stress vs. temperature curve the vessel is considered safe. The magnitude of the different factors influencing the final transition temperature are discussed and data for the Marviken reactor's pressure vessel are presented. At the end of the reactor's lifetime the estimated transition temperature is 115 deg C, which is below the maximum permissible value. A program for the study of strain ageing has been initiated owing to the uncertainty as to the extent of strain ageing at low strains. A study of a simple crack-arrest test, developed in Sweden, is in progress. An extensive irradiation-effects program on several steels is in progress. Results from tests on the Swedish carbon-manganese steels 2103/R3, SIS 142103 and SIS 142102, the low-alloy steels Degerfors DE-631A, Bofors NO 345 and Fortiweld

  3. Swedish Work on Brittle-Fracture Problems in Nuclear Reactor Pressure Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Grounes, M

    1966-03-15

    After a short review of the part of the Swedish nuclear energy program that is of interest in this context the Swedish reactor pressure vessels and the reasoning behind the choice of materials are surveyed. Problems and desirable aims for future reactors are discussed. Much work is now being done on new types of pressure vessel steels with high strength, low transition temperature and good corrosion resistance. These steels are of the martensitic austenitic type Bofors 2RMO (13 % Cr, 6 % Ni, 1. 5 % Mo) and of the ferritic martensitic austenitic type Avesta 248 SV (16 % Cr, 5 % Ni, 1 % Mo). An applied philosophy for estimating the brittle-fracture tendency of pressure vessels is described. As a criterion of this tendency we use the crack-propagation transition temperature, e. g. as measured by the Robertson isothermal crack-arrest test. An estimate of this transition temperature at the end of the reactor' s lifetime must take increases due to fabrication, welding, geometry, ageing and irradiation into account. The transition temperature vs. stress curve moves towards higher temperatures during the reactor' s lifetime. As long as this curve does not cross the reactor vessel stress vs. temperature curve the vessel is considered safe. The magnitude of the different factors influencing the final transition temperature are discussed and data for the Marviken reactor's pressure vessel are presented. At the end of the reactor's lifetime the estimated transition temperature is 115 deg C, which is below the maximum permissible value. A program for the study of strain ageing has been initiated owing to the uncertainty as to the extent of strain ageing at low strains. A study of a simple crack-arrest test, developed in Sweden, is in progress. An extensive irradiation-effects program on several steels is in progress. Results from tests on the Swedish carbon-manganese steels 2103/R3, SIS 142103 and SIS 142102, the low-alloy steels Degerfors DE-631A, Bofors NO 345 and Fortiweld

  4. Statement to International Conference on Fast Reactors and Related Fuel Cycles: Challenges and Opportunities, 7 December 2009, Kyoto, Japan

    International Nuclear Information System (INIS)

    Amano, Yukiya

    2009-01-01

    Full text: Distinguished Guests, Ladies and Gentlemen, It is my honour to address participants at this opening session of the International Conference on Fast Reactors and Related Fuel Cycles: Challenges and Opportunities, organized by the IAEA and hosted by the Japan Atomic Energy Agency. Fast reactor technology has the potential to ensure that energy resources which would last hundreds of years with the technology we are using today will actually last several thousand years. In other words it can withstand enormous increases in demand. This innovative technology also reduces the risk to the environment and helps to limit the burden that will be placed on future generations in the form of waste products. The coming year will be an exciting one for the development of fast-spectrum nuclear reactors. We expect to reach many important milestones: - the first criticality of the China Experimental Fast Reactor; - the restart of the Monju prototype fast reactor in Japan; and - the new insights we will gain through the end-of-life studies at the Phenix reactor in France. In the near future, new fast reactors will be commissioned: the 500MW(e) Prototype Fast Breeder Reactor in India, the first in a series of five of the same type, and the BN-800 reactor in the Russian Federation. Moreover, France, Japan, India, China and the Republic of Korea are preparing advanced prototypes, demonstration or commercial reactors for the 2020-2030 period. Nuclear power is set to be an increasingly important part of the global energy mix in the coming decades as demand for energy grows. Scores of countries in both the developed and developing world have told the IAEA that they are interested in introducing nuclear power. The 30 countries which already have nuclear power reactors are set to build more. This trend is likely to be accompanied by accelerated deployment of fast reactors. Continued advances in research and technology development are necessary to ensure improved economics and

  5. The fuzzy clearing approach for a niching genetic algorithm applied to a nuclear reactor core design optimization problem

    International Nuclear Information System (INIS)

    Sacco, Wagner F.; Machado, Marcelo D.; Pereira, Claudio M.N.A.; Schirru, Roberto

    2004-01-01

    This article extends previous efforts on genetic algorithms (GAs) applied to a core design optimization problem. We introduce the application of a new Niching Genetic Algorithm (NGA) to this problem and compare its performance to these previous works. The optimization problem consists in adjusting several reactor cell parameters, such as dimensions, enrichment and materials, in order to minimize the average peak-factor in a three-enrichment zone reactor, considering restrictions on the average thermal flux, criticality and sub-moderation. After exhaustive experiments we observed that our new niching method performs better than the conventional GA due to a greater exploration of the search space

  6. Particle swarm optimization with random keys applied to the nuclear reactor reload problem

    Energy Technology Data Exchange (ETDEWEB)

    Meneses, Anderson Alvarenga de Moura [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Nuclear; Fundacao Educacional de Macae (FUNEMAC), RJ (Brazil). Faculdade Professor Miguel Angelo da Silva Santos; Machado, Marcelo Dornellas; Medeiros, Jose Antonio Carlos Canedo; Schirru, Roberto [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Nuclear]. E-mails: ameneses@con.ufrj.br; marcelo@lmp.ufrj.br; canedo@lmp.ufrj.br; schirru@lmp.ufrj.br

    2007-07-01

    In 1995, Kennedy and Eberhart presented the Particle Swarm Optimization (PSO), an Artificial Intelligence metaheuristic technique to optimize non-linear continuous functions. The concept of Swarm Intelligence is based on the socials aspects of intelligence, it means, the ability of individuals to learn with their own experience in a group as well as to take advantage of the performance of other individuals. Some PSO models for discrete search spaces have been developed for combinatorial optimization, although none of them presented satisfactory results to optimize a combinatorial problem as the nuclear reactor fuel reloading problem (NRFRP). In this sense, we developed the Particle Swarm Optimization with Random Keys (PSORK) in previous research to solve Combinatorial Problems. Experiences demonstrated that PSORK performed comparable to or better than other techniques. Thus, PSORK metaheuristic is being applied in optimization studies of the NRFRP for Angra 1 Nuclear Power Plant. Results will be compared with Genetic Algorithms and the manual method provided by a specialist. In this experience, the problem is being modeled for an eight-core symmetry and three-dimensional geometry, aiming at the minimization of the Nuclear Enthalpy Power Peaking Factor as well as the maximization of the cycle length. (author)

  7. Particle swarm optimization with random keys applied to the nuclear reactor reload problem

    International Nuclear Information System (INIS)

    Meneses, Anderson Alvarenga de Moura; Fundacao Educacional de Macae; Machado, Marcelo Dornellas; Medeiros, Jose Antonio Carlos Canedo; Schirru, Roberto

    2007-01-01

    In 1995, Kennedy and Eberhart presented the Particle Swarm Optimization (PSO), an Artificial Intelligence metaheuristic technique to optimize non-linear continuous functions. The concept of Swarm Intelligence is based on the socials aspects of intelligence, it means, the ability of individuals to learn with their own experience in a group as well as to take advantage of the performance of other individuals. Some PSO models for discrete search spaces have been developed for combinatorial optimization, although none of them presented satisfactory results to optimize a combinatorial problem as the nuclear reactor fuel reloading problem (NRFRP). In this sense, we developed the Particle Swarm Optimization with Random Keys (PSORK) in previous research to solve Combinatorial Problems. Experiences demonstrated that PSORK performed comparable to or better than other techniques. Thus, PSORK metaheuristic is being applied in optimization studies of the NRFRP for Angra 1 Nuclear Power Plant. Results will be compared with Genetic Algorithms and the manual method provided by a specialist. In this experience, the problem is being modeled for an eight-core symmetry and three-dimensional geometry, aiming at the minimization of the Nuclear Enthalpy Power Peaking Factor as well as the maximization of the cycle length. (author)

  8. Christian – Muslim Relations in Nigeria: The Problems and Prospects

    African Journals Online (AJOL)

    Christian – Muslim Relations in Nigeria: The Problems and Prospects. ... Basic findings of this study show that Nigeria.s stability, democracy, and national ... must embrace Inter-religious dialogue which demands religions nurture, faith, trust, ...

  9. Pharmacist intervention in drug-related problems for patients with ...

    African Journals Online (AJOL)

    Trop J Pharm Res, October 2016; 15(10): 2275. Tropical Journal of ... medication errors in irrational drug use, while patient adherence ..... Drug-related problems identified from geriatric medication safety ... Ann. Pharmacother. 2005; 39:1423-.

  10. Using the internet: skill related problems in users’ online behavior

    NARCIS (Netherlands)

    van Deursen, Alexander Johannes Aloysius Maria; van Dijk, Johannes A.G.M.

    2009-01-01

    This study extends the conventional and superficial notion of measuring digital skills by proposing definitions for operational, formal, information and strategic skills. The main purpose was to identify individual skill related problems that users experience when navigating the Internet. In

  11. Review of xenon-133 production and related problems

    International Nuclear Information System (INIS)

    Barrachina, M.; Ropero, M.

    1980-01-01

    A literature survey is given on the production methods of fission xenon-133 and related problems, such as purification, metrological and dosimetric aspects, preparation of isotopic solutions, recycling, etc. 127 references are included. (Author) 127 refs

  12. Corrosion Induced Leakage Problem of the Radial Beam Port 1 of BAEC Triga Mark-II Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kalam, A.; Salam, M. A.; Sarder, M. A.; Rahman, M. M.; Rahman, M.; Rahman, A.; Chowdhury, A. Z.; Uddin, M. S.; Haque, M. M.; Zulquarnain, M.A., E-mail: kalambaec@yahoo.com [Reactor Operation and Maintenance Unit, Atomic Energy Research Establishment (AERE), Dhaka (Bangladesh)

    2014-08-15

    The BAEC reactor has so far been operated as per the technical specifications and procedures laid down in the SAR of the research reactor. The BP leakage problem of the BAEC research reactor was an issue that could lead to a situation close to a LOCA. Therefore, the matter was handled carefully, taking all measures so that such an incident could be prevented. Assistance of agencies outside BAEC was taken for solving the problem. It is understood that the silicone rubber lining of the encirclement clamp may become damaged by neutron irradiation. Therefore, while designing the clamp, provisions were kept such that it can be dismantled and reinstalled again following lining replacement. As a moderately aged facility, the ageing management BAEC TRIGA research reactor deserves significant attention. BAEC, together with its strategic partners, are doing what is needed in this regard.

  13. Performance Monitoring for Nuclear Safety Related Instrumentation at PUSPATI TRIGA Reactor (RTP)

    International Nuclear Information System (INIS)

    Zareen Khan Abdul Jalil Khan; Ridzuan Abdul Mutalib; Mohd Sabri Minhat

    2015-01-01

    The Reactor TRIGA PUSPATI (RTP) at Malaysia Nuclear Agency is a TRIGA Mark II type reactor and pool type cooled by natural circulation of light water. This paper describe on performance monitoring for nuclear safety related instrumentation in TRIGA PUSPATI Reactor (RTP) of based on various parameter of reactor safety instrument channel such as log power, linear power, Fuel temperature, coolant temperature will take into consideration. Methodology of performance on estimation and monitoring is to evaluate and analysis of reactor parameters which is important of reactor safety and control. And also to estimate power measurement, differential of log and linear power and fuel temperature during reactor start-up, operation and shutdown .This study also focus on neutron power fluctuation from fission chamber during reactor start-up and operation. This work will present result of performance monitoring from RTP which indicated the safety parameter identification and initiate safety action on crossing the threshold set point trip. Conclude that performance of nuclear safety related instrumentation will improved the reactor control and safety parameter during reactor start-up, operation and shutdown. (author)

  14. A flow reactor for the flow supercritical water oxidation of wastes to mitigate the reactor corrosion problem

    International Nuclear Information System (INIS)

    Chitanvis, S.M.

    1994-01-01

    We have designed a flow tube reactor for supercritical water oxidation of wastes that confines the oxidation reaction to the vicinity of the axis of the tube. This prevents high temperatures and reactants as well as reaction products from coming in intimate contact with reactor walls. This implies a lessening of corrosion of the walls of the reactor. We display numerical simulations for a vertical reactor with conservative design parameters that illustrate our concept. We performed our calculations for the destruction of sodium nitrate by ammonium hydroxide In the presence of supercritical water, where the production of sodium hydroxide causes corrosion. We have compared these results with that for a horizontal set-up where the sodium hydroxide created during the reaction ends up on the floor of the tube, implying a higher probability of corrosion

  15. Technical Meeting on Fast Reactors and Related Fuel Cycle Facilities with Improved Economic Characteristics. Working Material

    International Nuclear Information System (INIS)

    2013-01-01

    The objectives of the meeting were: - To identify the main issues and technical features that affect capital and energy production costs of fast reactors and related fuel cycle facilities; - To present fast reactor concepts and designs with enhanced economic characteristics, as well as innovative technical solutions (components, subsystems, etc.) that have the potential to reduce the capital costs of fast reactors and related fuel cycle facilities; - To present energy models and advanced tools for the cost assessment of innovative fast reactors and associated nuclear fuel cycles; - To discuss the results of studies and on-going R&D activities that address cost reduction and the future economic competitiveness of fast reactors; and - To identify research and technology development needs in the field, also in view of new IAEA initiatives to help and support Member States in improving the economic competitiveness of fast reactors and associated nuclear fuel cycles

  16. Technical Meeting on Fast Reactors and Related Fuel Cycle Facilities with Improved Economic Characteristics. Presentations

    International Nuclear Information System (INIS)

    2013-01-01

    The objectives of the meeting were: • To identify the main issues and technical features that affect capital and energy production costs of fast reactors and related fuel cycle facilities; • To present fast reactor concepts and designs with enhanced economic characteristics, as well as innovative technical solutions (components, subsystems, etc.) that have the potential to reduce the capital costs of fast reactors and related fuel cycle facilities; • To present energy models and advanced tools for the cost assessment of innovative fast reactors and associated nuclear fuel cycles; • To discuss the results of studies and ongoing R&D activities that address cost reduction and the future economic competitiveness of fast reactors; • To identify research and technology development needs in the field, also in view of new IAEA initiatives to help and support Member States in improving the economic competitiveness of fast reactors and associated nuclear fuel cycles

  17. Solution of safety problems for nuclear power plants with WWER-440 reactors

    International Nuclear Information System (INIS)

    Krett, V.; Pernitsa, R.; Pfann, Ya.; Zbeglik, J.

    1982-01-01

    Institute of nuclear research (INR) of Czechoslovakian Atomic Energy Commission isto fulfil the supervision functions within the field of nuclear power research and development. The problems of safe operation ensurance for the nuclear power plants (NPP) with WWER-440 reactors are studied within the frame of sever major issues: code standardization and devolopment of guiding materials for the state supervision; neutronic and thermohydrolic data processing for the accident analysis; operation reliability studies of the safety systems and estimates of separate component failure importance; assessment of the accidents resulting from the equipment misfunctioning and component failures; development of a controlled reliability program; evaluation of the atomic installationsimpact on the environment; ensurence of the reactor vessel reliability and durability under irradiation. The NPP safety analysis incorporates the calculations of transient and accidental regimes for the core, the primary loop and the entire plant. A number of codes has been produced which allow to determine the state of fuel elements during operation just before the accidents assessed, thermohydrolic conditions in the coolant and the temperature distribution within the fuel both for the stationary reactor conditions and for transient regimes. A mathematical model has been deveoloped, including the description of all the primary loop major components. The Soviet code DYNAMIKA has been adopted and adjusted for EC-1040 computer, there by the accident analysis for the entire NPP has been made possible. On the basis of american SAFTE code a faster SAFEDO-2 code has been developed employing the Monte Carlo method for the accident analysis of a complex system described by means of a failure tree. The discussed codes are used at the data assessment for the accident analysis part of the safety reports as well as for the reliability evaluation of the emergency core cooling system [ru

  18. Integrity of Safety-Related Fast Reactor Structures

    International Nuclear Information System (INIS)

    Rose, R.T.; Tomkins, B.

    1981-01-01

    The LMFBR contains several structural items whose integrity must be safeguarded during the life of the plant. These items include the main core support structures (strongback, diagrid) and the primary tank to which these structures are attached. In order to demonstrate an acceptable level of structural integrity, the chosen design philosophy must be supported by both analytical and experimental evidence. This paper describes the current approaches in the UK to these requirements. Section 2 describes the materials mechanical properties tests performed to date on both fracture toughness and fatigue crack growth in Type 316 austenitic stainless steel plate and weldments. This data illustrates the problems in identifying the relevant materials fracture parameters for use in assessments. Section 3 shows the test programmes in hand to extend the materials programmes to tests on structural features (mainly welded wide plate tests) which incorporate the complexity of weldments in a structural context. This includes experimental evidence on the effects of local weld residual stresses on structural failure. Various routes are open for the integrity assessment of FR structures. These are discussed in Section 4 but in effect they reduce to a fracture mechanics approach using some technique to cope with elastic-plastic fracture. The main problems at present relate to our ability in analysis to cope with residual stresses and the post-initiation region of the fracture resistance curve. Also, there is the problem of initial defect sizing by current NDE techniques. Current conservative analytical assessments give acceptable defect sizes of order a few millimetres in irradiated weldments. Finally, Section 5 discusses the options open in design to cope with safety related structures under normal and abnormal loading conditions. It is clear that several options exist in design to satisfy the demand for high integrity

  19. Some studies related to decommissioning of nuclear reactors

    International Nuclear Information System (INIS)

    Bergman, C.; Menon, S.

    1990-02-01

    Decommissioning of large nuclear reactors has not yet taken place in the Nordic countries. Small nuclear installations, however, have been dismantled. This NKA-programme has dealt with some interesting and important factors which have to be analysed before a large scale decommissioning programme starts. Prior to decommissioning, knowledge is required regarding the nuclide inventory in various parts of the reactor. Measurements were performed in regions close to the reactor tank and the biological shield. These experimental data are used to verify theoretical calculations. All radioactive waste generated during decommissioning will have to be tansported to a repository. Studies show that in all the Nordic countries there are adequate transport systems with which decommissioning waste can be transported. Another requirement for orderly decommissioning planning is that sufficient information about the plant and its operation history must be available. It appears that if properly handled and sorted, all such information can be extracted from existing documentation. (authors)

  20. A fluid-solid finite element method for the analysis of reactor safety problems

    International Nuclear Information System (INIS)

    Mitra, Santanu; Kumar, Ashutosh; Sinhamahapatra, K.P.

    2006-01-01

    The work presented herein can broadly be categorized as a fluid-structure interaction problem. The response of a circular cylindrical structure subjected to cross flow is examined using the finite element method for both the liquid and the structure domains. The cylindrical tube is mounted elastically at the ends and is free to move under the action of the unsteady flow-induced forces. The fluid is considered to be acoustic compressible and viscous. A Galerkin finite element method implemented on a triangular mesh is used to solve the time-dependent Navier-Stokes equations. The cylinder motion is modeled using a five-degrees of freedom generalized shell element structural dynamics model. The numerical simulations of the response of the calandria tubes/pressure tubes, adjustor rod and shut-off rod of a nuclear reactor are presented. A few typical results are presented to assess the accuracy and applicability of the developed modules

  1. Worldwide assessment of steam-generator problems in pressurized-water-reactor nuclear power plants

    International Nuclear Information System (INIS)

    Woo, H.H.; Lu, S.C.

    1981-01-01

    Objective is to assess the reliability of steam generators of pressurized water reactor (PWR) power plants in the United States and abroad. The assessment is based on operation experience of both domestic and foreign PWR plants. The approach taken is to collect and review papers and reports available from the literature as well as information obtained by contacting research institutes both here and abroad. This report presents the results of the assessment. It contains a general background of PWR plant operations, plant types, and materials used in PWR plants. A review of the worldwide distribution of PWR plants is also given. The report describes in detail the degradation problems discovered in PWR steam generators: their causes, their impacts on the performance of steam generators, and the actions to mitigate and avoid them. One chapter is devoted to operating experience of PWR steam generators in foreign countries. Another discusses the improvements in future steam generator design

  2. Performance characteristics of specified power reactors in multidimensional neutron diffusion problems

    International Nuclear Information System (INIS)

    Kim, M.G.

    1980-01-01

    The multigroup neutron diffusion equations with the constraint of specified power distributions are investigated by the application of the straight-line method which can be considered as the limiting case of zero mesh space in the finite difference method. The standard partial differential form of the diffusion equation is reduced to sets of ordinary differential equations and then converted into sets of integral equations by using Green's functions defined on the pseudo straight lines. Coupling of each straight line to the adjacent lines arises from the application of a three-point central difference formula. The interfaces encountered between two regions are taken into account by imposing the continuity conditions for the grown fluxes and net currents with Taylor expansions of internal fluxes at the interface positions. A few sample problems are selected to test the validity of the method. It is found that the proposed method of solution is similar to the finite Fourier sine transform. Numerical results for the solutions obtained by the method of straight lines are compared with the results of the exact analytical solutions for simple geometries. These comparisons indicate that the proposed method is compatible with the analytical method, and in some problems considered the straight-line solutions are much more efficient than the exact solutions. The method is also extended to the reactor kinetics problem by expressing the kinetics parameters in terms of the basis functions which are used to obtain the solutions of the steady-state neutron diffusion equations

  3. Regulatory trends and practices related to nuclear reactor decommissioning

    International Nuclear Information System (INIS)

    Cantor, R.A.

    1984-01-01

    In the next several decades, the electric utility industry will be faced with the retirement of 50,000 megawatts (mW) of nuclear capacity. Responsibility for the financial and technical burdens this activity entails has been delegated to the utilities operating the reactors. However, the operators will have to perform the tasks of reactor decommissioning within the regulatory environment dictated by federal, state and local regulations. The purpose of this paper is to highlight some of the current and likely trends in regulations and regulatory practices that will significantly affect the costs, technical alternatives and financing schemes encountered by the electric utilities and their customers

  4. The gas-cooled high temperature reactor. Perspectives, problems and programmes

    International Nuclear Information System (INIS)

    Beckurts, K.H.; Engelmann, P.; Erb, D.E.

    1977-01-01

    For nearly 20 years extensive research and development programmes on helium-cooled high temperature reactors (HTR) have been carried out in several countries of the world. As a result of the long-standing efforts, satisfactory solutions have been found for many of the basic problems of this new reactor system, particularly in the field of high temperature fuels and materials technology. Three small experimental plants have been operated successfully over extended periods of time. Prototype steam-cycle plants of 300MW(e) are under way at Fort St. Vrain (full-power operation scheduled for 1977) and at Schmehausen (scheduled for 1979). Major delays have occurred in the construction and commissioning of these plants for various reasons but do not reveal specific problems of the HTR. Commercial market introduction of the steam-cycle electricity generating system has been attempted, but the first approach has not been successful. Major efforts both by governments and industry are now required to ensure a successful second approach. To reach competitivity with established nuclear power systems and to take full advantage of the fuel conservation potential of the HTR requires the implementation of the closed thorium fuel cycle on a commercial scale. While some key steps of this cycle have been implemented on a laboratory scale, progress towards a prototype recycling facility has been slow. Closing the thorium fuel cycle represents a major challenge and can only be achieved in a close international collaboration. The paper discusses the world-wide status and potential of HTR technology and reviews the major international development programmes. (author)

  5. Travel-related health problems in Japanese travelers.

    Science.gov (United States)

    Mizuno, Yasutaka; Kudo, Koichiro

    2009-09-01

    Although the number of Japanese individuals traveling abroad has increased steadily, reaching approximately 17.3 million in 2007, the incidence of various travel-related health problems in Japan remains unknown. The travel-related health problems of Japanese travelers returning to Japan from abroad are analyzed by assessing the records. Data were collected retrospectively on returning travelers who visited the authors' travel clinic during the period from January 2005 through to December 2006 with any health problem acquired overseas. A total of 345 patients were included in this study (200 male, 145 female; average age, 34+/-12.3 years). Reasons for travel included leisure (45.8%); business (39.1%); visiting friends and relatives or accompanying other travelers (8.7%); volunteering (3.8%); and long stays in order to study or live (2.6%). The most visited destination was Asia (n=260), followed by Africa (n=105). The most commonly reported health problems were gastro-intestinal infections (39.1%), followed by respiratory tract infections (16.2%), animal bites (8.1%), and skin problems (5.8%). Together, malaria and dengue accounted for 10% of diagnoses in 125 febrile patients (36.2%). Although the profile of travel-related health problems in Japanese travelers is similar to that of Western travelers, the characteristics of travel were quite different. Therefore Japanese travel advice should be tailored to suit the Japanese traveler.

  6. Decision making on the Breeder reactor in Britain and the United States: problems and solutions in the plutonium economy

    International Nuclear Information System (INIS)

    Rydell, R.J.

    1980-01-01

    One objective of this study is to develop a framework of analysis that is useful for investigating the conditions shaping the respective roles of science and politics in decision making on technology policy. The analytical framework used focuses upon the interactive R and D process and specifies the factors affecting change in and of that process. The distinguishing feature of this new analytical framework is its utility for investigating how participants in and R and D process go about defining and solving a growing variety of problems that they encounter as the costs, impacts, and stakes of technological change become more readily apparent. The framework is then applied to a particularly complex and politically controversial technology, the nuclear breeder reactor. Britain and the United States, the original pioneers of technology utilizing plutonium to produce electricity, were singled out in order to test the utility of the analytical framework for the comparative study of the R and D decision-making process. Although the study does not purport to have exhausted all possible interpretations of this complex subject, the results of the study suggest that the interactive R and D process represents an improvement over conventional modes of conceptualizing how R and D policies are formulated and changed. Efforts to resolve major national and international problems relating to science and technology will ultimately succeed only to the extent that these efforts are grounded in a deeper understanding of the conditions affecting how these problems are defined and approached in actual decision-making environments

  7. The gas-cooled high temperature reactor: perspectives, problems and programmes

    International Nuclear Information System (INIS)

    Beckurts, K.H.; Engelmann, P.; Erb, D.E.

    1977-01-01

    For nearly 20 years, extensive research and development programs on Helium-cooled high-temperature reactors (HTR) have been carried out in several countries of the world, in particular in Germany and in the United States. This reactor system offers major potential advantages as a source of electricity or of nuclear process heat: it shows high nuclear fuel conversion efficiency, permitting a better utilization of uranium and in particular of thorium resources; it offers a high degree of inherent nuclear safety and thus a good potential for adoption to very strict safety standards; it permits high-efficiency electricity generation using either the indirect steam or the direct Helium cycle; dry air cooling can be employed without major economic penalties; it permits direct use of the nuclear heat for the production of gaseous or liquid secondary fuels from coal and other fossil fuels or - on a more extended time scale - by thermochemical water splitting. As a result of the longstanding efforts, satisfactory solutions have been found for many of the basic problems of this new reactor system, particularly in the field of high-temperature fuels and materials technology. Three small experimental plants - Peach Bottom in USA, Dragon in England, and AVR in Germany - have been operated successfully over extended periods of time. The AVR is still in operation; since 1974 it has performed satisfactorily with an average gas outlet temperature of 950 0 C. Prototype steam-cycle plants of 300 MW(e) are underway at Fort St. Vrain, USA (full-power operation scheduled for 1977), and at Schmehausen, Germany (scheduled for 1979). Major delays have occured in the construction and commissioning of these plants; they are due to various reasons and do not reveal specific problems of the HTR. Commercial market introduction of the steam-cycle electricity generating system has been attempted, but the first approach has not been successfull. Major effects by both government and industry are

  8. Some human-related problems in radiation protection

    International Nuclear Information System (INIS)

    Yoshizawa, Yasuo

    1980-01-01

    Radiation protection includes both human and source-related problems. The human problems have not only medical but also social aspects, such as labor management. Special attention should be paid to the fact that the subject of radiation protection is not a human being as living thing but as member of society. ICRP recommended that conditions of work can be divided into two classed, working condition A and B, according to annual exposure. This application is of great value to radiation protection practice. Nevertheless the legal regulations do not adopt it yet. The present condition of the medical surveillance of radiation workers is not appropriate from the scientific standpoint. This is the difficult problem which is caused by the delay of the legal application of ICRP recommendation. Compensation for occupational radiation hazards should be overlooked. This problem have been investigated by an authorized committee, but a number of unsolved problems still remain. (author)

  9. A basic plan of micro reactor for the promotion of nuclear literacy problems in realization of the reactor

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Takashi [Graduate School of Energy Science, Kyoto University, Kyoto (Japan); Yoshiki, Nobuya [Central Research Inst. of Electric Power Industry, Tokyo (Japan); Nakagawa, Haruo [Hitachi Ltd., Tokyo (Japan)

    2001-04-01

    It is difficult for new sciences and big technologies such as life sciences, nuclear energy, biotechnology, etc. to achieve the appropriate public understanding. One of the issues is the lack of scientific literacy in the public. We propose a new type of nuclear reactor to prepare the opportunity for the public to be acquainted with the information and technology of the nuclear science and engineering. This reactor for interpretation is a symbolic facility adjacent to the scientific and technological museum. Features of the interpretative reactor must be safety and openness. The safety is satisfied by the excess reactivity less than 0.5% {delta}k/k and little burn up based on the thermal output less than 1 W. (author)

  10. A basic plan of micro reactor for the promotion of nuclear literacy problems in realization of the reactor

    International Nuclear Information System (INIS)

    Murata, Takashi; Yoshiki, Nobuya; Nakagawa, Haruo

    2001-01-01

    It is difficult for new sciences and big technologies such as life sciences, nuclear energy, biotechnology, etc. to achieve the appropriate public understanding. One of the issues is the lack of scientific literacy in the public. We propose a new type of nuclear reactor to prepare the opportunity for the public to be acquainted with the information and technology of the nuclear science and engineering. This reactor for interpretation is a symbolic facility adjacent to the scientific and technological museum. Features of the interpretative reactor must be safety and openness. The safety is satisfied by the excess reactivity less than 0.5% Δk/k and little burn up based on the thermal output less than 1 W. (author)

  11. Special needs of the developing countries as related to research reactors

    International Nuclear Information System (INIS)

    1979-02-01

    After a short review of the particular operating conditions for research reactors in developing countries, these reactors are presented in a tabular survey. The appendix deals mostly with the possible ways to reduce the degree of enrichment of the uranium fuel. This attempted reduction is closely related with the attempts to improve the non-proliferation policy

  12. Experimental Methods Related to Coupled Fast-Thermal Systems at the RB Reactor

    International Nuclear Information System (INIS)

    Pesic, M.

    2002-01-01

    In addition to the review of RB reactor characteristics this presentation is focused on the coupled fast-thermal systems achieved at the reactor. The following experimental methods are presented: neutron spectra measurements; steady state experiments and kinetic measurements ( β eff ) related to the coupled fast-thermal cores

  13. International conference on fast reactors and related fuel cycles (FR09): Challenges and opportunities. CN-176 presentations

    International Nuclear Information System (INIS)

    2009-01-01

    and development, as well as in design, has not been reported in a coordinated manner, which has made planning and implementation of expensive research and technology development programmes rather difficult. There is a perceived need for an appropriate forum to achieve the twin objectives of exchanging experience and innovative ideas among experts, and of sharing knowledge and mentoring, whereby experienced scientists and technologists, as well as fast reactor programme managers, would share their perspectives with the future generation of young scientists and technologists, helping them to choose research problems of eminence and pursue their careers to meet the challenges of the development of fast reactors with recycle. After almost 20 years, this is also the appropriate time, as fast reactor programmes are currently on an accelerated growth path in many countries of the world. It is in light of this that the IAEA convened on 7-11 December 2009 in Kyoto, Japan, the International Conference on 'Fast Reactors and Related Fuel Cycles - Challenges and Opportunities (FR09)', hosted by the Japan Atomic Energy Agency. This conference aimed at promoting the exchange of information on national and multinational programmes and new developments and experience, with the goal of identifying and critically reviewing problems of importance, and stimulating and facilitating cooperation, development and successful deployment of fast reactors in an expeditious manner

  14. Press problem related to nuclear energy news reporting

    International Nuclear Information System (INIS)

    Arai, Mitsuo

    2008-01-01

    Since the event of Niigataken Chuetsu-oki Earthquake in 2007 and the subsequent press reports on damage of nuclear power station after it, a stance of media is being questioned. In order to clear this problem, basic organizational structure of the press related to nuclear energy news was analyzed. Local news department, social news department, science news department and economical news department involve in nuclear energy news the accordance with their own situations and concerns. This structure makes problem of nuclear energy news reporting complicated. Changing this system is required but very difficult. It is concluded that the press problem around nuclear energy news is strange. (author)

  15. Drug-related problems and pharmacy interventions in community practice

    DEFF Research Database (Denmark)

    Westerlund, Tommy; Almarsdóttir, Anna Birna; Melander, Arne

    1999-01-01

    Objectives. (1) To document types and number of drug-related problems identified by community pharmacy personnel in Sweden; (2) to determine relationships among the types and number of problems identified and the gender, age and number of prescribed drugs in patients; and (3) to document the inte......Objectives. (1) To document types and number of drug-related problems identified by community pharmacy personnel in Sweden; (2) to determine relationships among the types and number of problems identified and the gender, age and number of prescribed drugs in patients; and (3) to document...... the interventions made by pharmacy personnel with patients and prescribers. Method. Random samples of pharmacists, prescriptionists and pharmacy technicians were drawn nationwide in Sweden; 144 (63 per cent) of the employees fulfilling the inclusion criteria agreed to take part. The participants documented drug......-related problems, interventions and patient variables on a data collection form, and tallied the number of patients they served on another form. Setting. One hundred and sixteen community pharmacies and 12 outpatient hospital pharmacies. Key findings. One problem or more was identified among 2.5 per cent...

  16. Decommissioning of the research nuclear reactor IRT-M and problems connected with radioactive waste

    International Nuclear Information System (INIS)

    Abramidze, S.P.; Katamadze, N.M.; Kiknadze, G.G.; Saralidze, Z.K.

    2000-01-01

    The nuclear research reactor IRT-2000 is described, along with modifications and upgrades made over the past three decades. Considerations are outlined which followed a decision to shut-down the reactor and to dismantle it. (author)

  17. General principles of nuclear safety management related to research reactor decommissioning

    International Nuclear Information System (INIS)

    Banciu, Ortenzia; Vladescu, Gabriela

    2003-01-01

    The paper contents the general principles applicable to the decommissioning of research reactors to ensure a proper nuclear safety management, during both decommissioning activities and post decommissioning period. The main objective of decommissioning is to ensure the protection of workers, population and environment against all radiological and non-radiological hazards that could result after a reactor shutdown and dismantling. In the same time, it is necessary, by some proper provisions, to limit the effect of decommissioning for the future generation, according to the new Romanian, IAEA and EU Norms and Regulations. Assurance of nuclear safety during decommissioning process involves, in the first step, to establish of some safety principles and requirements to be taken into account during whole process. In the same time, it is necessary to perform a series of analyses to ensure that the whole process is conducted in a planned and safe manner. The general principles proposed for a proper management of safety during research reactor decommissioning are as follows: - Set-up of all operations included in a Decommissioning Plan; - Set-up and qualitative evaluation of safety problems, which could appear during normal decommissioning process, both radiological and nonradiological risks for workers and public; - Set-up of accident list related to decommissioning process the events that could appear both due to some abnormal working conditions and to some on-site and off-site events like fires, explosions, flooding, earthquake, etc.); - Development and qualitative/ quantitative evaluation of scenarios for each incidents; - Development (and evaluation) of safety indicator system. The safety indicators are the most important tools used to assess the level of nuclear safety during decommissioning process, to discover the weak points and to establish safety measures. The paper contains also, a safety case evaluation (description of facility according to the decommissioning

  18. New approaches of the potential field for QPSO algorithm applied to nuclear reactor reload problem

    International Nuclear Information System (INIS)

    Nicolau, Andressa dos Santos; Schirru, Roberto

    2015-01-01

    Recently quantum-inspired version of the Particle Swarm Optimization (PSO) algorithm, Quantum Particle Swarm Optimization (QPSO) was proposed. The QPSO algorithm permits all particles to have a quantum behavior, where some sort of 'quantum motion' is imposed in the search process. When the QPSO is tested against a set of benchmarking functions, it showed superior performances as compared to classical PSO. The QPSO outperforms the classical one most of the time in convergence speed and achieves better levels for the fitness functions. The great advantage of QPSO algorithm is that it uses only one parameter control. The critical step or QPSO algorithm is the choice of suitable attractive potential field that can guarantee bound states for the particles moving in the quantum environment. In this article, one version of QPSO algorithm was tested with two types of potential well: delta-potential well harmonic oscillator. The main goal of this study is to show with of the potential field is the most suitable for use in QPSO in a solution of the Nuclear Reactor Reload Optimization Problem, especially in the cycle 7 of a Brazilian Nuclear Power Plant. All result were compared with the performance of its classical counterpart of the literature and shows that QPSO algorithm are well situated among the best alternatives for dealing with hard optimization problems, such as NRROP. (author)

  19. New approaches of the potential field for QPSO algorithm applied to nuclear reactor reload problem

    Energy Technology Data Exchange (ETDEWEB)

    Nicolau, Andressa dos Santos; Schirru, Roberto, E-mail: andressa@lmp.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2015-07-01

    Recently quantum-inspired version of the Particle Swarm Optimization (PSO) algorithm, Quantum Particle Swarm Optimization (QPSO) was proposed. The QPSO algorithm permits all particles to have a quantum behavior, where some sort of 'quantum motion' is imposed in the search process. When the QPSO is tested against a set of benchmarking functions, it showed superior performances as compared to classical PSO. The QPSO outperforms the classical one most of the time in convergence speed and achieves better levels for the fitness functions. The great advantage of QPSO algorithm is that it uses only one parameter control. The critical step or QPSO algorithm is the choice of suitable attractive potential field that can guarantee bound states for the particles moving in the quantum environment. In this article, one version of QPSO algorithm was tested with two types of potential well: delta-potential well harmonic oscillator. The main goal of this study is to show with of the potential field is the most suitable for use in QPSO in a solution of the Nuclear Reactor Reload Optimization Problem, especially in the cycle 7 of a Brazilian Nuclear Power Plant. All result were compared with the performance of its classical counterpart of the literature and shows that QPSO algorithm are well situated among the best alternatives for dealing with hard optimization problems, such as NRROP. (author)

  20. Special relativity. An introduction with 200 problems and solutions

    International Nuclear Information System (INIS)

    Tsamparlis, Michael

    2010-01-01

    This textbook develops Special Relativity in a systematic way assuming no prior knowledge of Relativity; however the student is assumed to be familiar with the basics of the standard vector calculus. The approach is structural in the sense that it develops Special Relativity in Minkowski space following the same steps with the development of Newtonian Physics in Euclidian space. A second characteristic of the book is that it discusses the mathematics of the theory independently of the physical principles, so that the reader will appreciate its role in the development of the physical theory. The book is intended to be used both as a text-book for a teaching course in Special Relativity but also as a reference book for the future. In that respect it is linked to an online repository with more than 500 problems, carefully classified according to subject area and solved in detail, providing an independent problem book on Special Relativity. (orig.)

  1. Special relativity. An introduction with 200 problems and solutions

    Energy Technology Data Exchange (ETDEWEB)

    Tsamparlis, Michael [Athens Univ., Zografos (Greece). Dept. of Astrophysics, Astronomy and Mechanics

    2010-07-01

    This textbook develops Special Relativity in a systematic way assuming no prior knowledge of Relativity; however the student is assumed to be familiar with the basics of the standard vector calculus. The approach is structural in the sense that it develops Special Relativity in Minkowski space following the same steps with the development of Newtonian Physics in Euclidian space. A second characteristic of the book is that it discusses the mathematics of the theory independently of the physical principles, so that the reader will appreciate its role in the development of the physical theory. The book is intended to be used both as a text-book for a teaching course in Special Relativity but also as a reference book for the future. In that respect it is linked to an online repository with more than 500 problems, carefully classified according to subject area and solved in detail, providing an independent problem book on Special Relativity. (orig.)

  2. Special Relativity An Introduction with 200 Problems and Solutions

    CERN Document Server

    Tsamparlis, Michael

    2010-01-01

    This textbook develops Special Relativity in a systematic way assuming no prior knowledge of Relativity; however the student is assumed to be familiar with the basics of the standard vector calculus. The approach is structural in the sense that it develops Special Relativity in Minkowski space following the same steps with the development of Newtonian Physics in Euclidian space. A second characteristic of the book is that it discusses the mathematics of the theory independently of the physical principles, so that the reader will appreciate its role in the development of the physical theory. The book is intended to be used both as a text-book for a teaching course in Special Relativity but also as a reference book for the future. In that respect it is linked to an online repository with more than 500 problems, carefully classified according to subject area and solved in detail, providing an independent problem book on Special Relativity.

  3. The problem of non-discrimination in labor relations

    OpenAIRE

    Вишновецька, Світлана Василівна; Національний авіаційний університет; Пінчук, Ольга Борисівна; Національний авіаційний університет

    2015-01-01

    The problem of discrimination on the grounds of gender and age in the field of labor relations are investigated in the article. International and Ukrainian legal regulation of non-discrimination as a guarantee of the right to work was analyzed; solutions to the problem are proposed in the article. The different points of view on the concept of discrimination in labor relations were studied by the authors. It was founded that discrimination by age and gender are the most extended forms of disc...

  4. European Union: Review of fast reactor related activities

    International Nuclear Information System (INIS)

    Goethem, G. van; Hugon, M.

    1998-01-01

    The European Commission (EC) continued its fast reactor research activities on the same lines as in the past, but with the main emphasis on partitioning and transmutation (P and T) of long-lived radionuclides. The work was carried out by research institutions in the Member States and by the EC Joint Research Centre (JRC) as cost shared actions. The JRC has also been performing its own programme through institutional and competitive research activities. The JRC institutes involved in these studies are the Institute of Systems, Informatics and Safety (ISIS) in Ispra (I), the Institute for Transuranium Elements (ITU) in Karlsruhe (D) and the Institute for Advanced Materials in Petten. This paper summarizes the main activities performed in the field of (i) fast reactor safety and of (ii) partitioning and transmutation. (author)

  5. Operational limitations of light water reactors relating to fuel performance

    International Nuclear Information System (INIS)

    Cheng, H.S.

    1976-07-01

    General aspects of fuel performance for typical Boiling and Pressurized Water Reactors are presented. Emphasis is placed on fuel failures in order to make clear important operational limitations. A discussion of fuel element designs is first given to provide the background information for the subsequent discussion of several fuel failure modes that have been identified. Fuel failure experiences through December 31, 1974, are summarized. The operational limitations that are required to mitigate the effects of fuel failures are discussed

  6. Application of the SHARP Toolkit to Sodium-Cooled Fast Reactor Challenge Problems

    Energy Technology Data Exchange (ETDEWEB)

    Shemon, E. R. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Yu, Y. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Kim, T. K. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2017-09-30

    The Simulation-based High-efficiency Advanced Reactor Prototyping (SHARP) toolkit is under development by the Nuclear Energy Advanced Modeling and Simulation (NEAMS) Campaign of the U.S. Department of Energy, Office of Nuclear Energy. To better understand and exploit the benefits of advanced modeling simulations, the NEAMS Campaign initiated the “Sodium-Cooled Fast Reactor (SFR) Challenge Problems” task, which include the assessment of hot channel factors (HCFs) and the demonstration of zooming capability using the SHARP toolkit. If both challenge problems are resolved through advanced modeling and simulation using the SHARP toolkit, the economic competitiveness of a SFR can be significantly improved. The efforts in the first year of this project focused on the development of computational models, meshes, and coupling procedures for multi-physics calculations using the neutronics (PROTEUS) and thermal-hydraulic (Nek5000) components of the SHARP toolkit, as well as demonstration of the HCF calculation capability for the 100 MWe Advanced Fast Reactor (AFR-100) design. Testing the feasibility of the SHARP zooming capability is planned in FY 2018. The HCFs developed for the earlier SFRs (FFTF, CRBR, and EBR-II) were reviewed, and a subset of these were identified as potential candidates for reduction or elimination through high-fidelity simulations. A one-way offline coupling method was used to evaluate the HCFs where the neutronics solver PROTEUS computes the power profile based on an assumed temperature, and the computational fluid dynamics solver Nek5000 evaluates the peak temperatures using the neutronics power profile. If the initial temperature profile used in the neutronics calculation is reasonably accurate, the one-way offline method is valid because the neutronics power profile has weak dependence on small temperature variation. In order to get more precise results, the proper temperature profile for initial neutronics calculations was obtained from the

  7. Anxiety Sensitivity and Sleep-Related Problems in Anxious Youth

    Science.gov (United States)

    Weiner, Courtney L.; Elkins, Meredith; Pincus, Donna; Comer, Jonathan

    2015-01-01

    Anxiety disorders constitute the most common mental health disturbance experienced by youth. Sleep-related problems (SRPs) are highly prevalent among anxious youth and encompass a variety of problems including nighttime fears, insomnia, and refusal to sleep alone. Given that chronic sleep disturbance is associated with a range of behavioral and physical problems in youth and predicts future psychopathology, it is important to elucidate the nature of SRPs in anxious youth. The present study investigated the relationship between sleep problems and anxiety sensitivity in a sample of 101 anxious youth, ages 6–17. Heightened anxiety sensitivity significantly predicted prolonged sleep onset latency across the sample, even after accounting for severity of anxiety, depression, and age. Results support previous research indicating that SRPs are common among anxious youth and suggest that anxiety sensitivity may play a particularly important role in sleep onset latency. PMID:25863826

  8. Assessment of the environment-related problems and prospects of ...

    African Journals Online (AJOL)

    The study attempted to assess the environment-related problems and prospects of vegetable production in peri – urban areas of Lagos state, Nigeria. A total of one hundred and twenty (120) farmers were interviewed. Data collected were analyzed using frequency, percentages and Pearson Product Moment Correlation ...

  9. Indoor and Outdoor Air Pollution- related Health Problem in Ethiopia ...

    African Journals Online (AJOL)

    Background: The health effects of air pollution are generally global problems, but they have, since recently become issues of particular concern for developing countries. This review assessed the situation of air pollution and related health effects in the context of Ethiopia. Methods: The materials reviewed in this publication ...

  10. RUSSIAN CORPORATIONS: THE PROBLEM OF INTRACORPORATE RELATIONS AND INTERESTS

    Directory of Open Access Journals (Sweden)

    Olga Brizhak

    2015-09-01

    Full Text Available The article actualizes the problem of the study of intra-corporate relations and economic interests of the various economic actors involved in the corporate environment of the Russian economy. The author considers the specific conditions of socio-economic and innovative development of Russian big business.

  11. a survey on drug related problems in cervical cancer patients

    African Journals Online (AJOL)

    userpc

    Cisplatin/5FU/paclitaxel. 6. 9.23. 6. Seizure. Cisplatin. 2. 3.08. 7. Loss of hair. Cisplatin/5FU/Paclitaxel. 3. 4.62. 8. Nephrotoxicity. Cisplatin. 3. 4.62. 9. Hypotension. Paclitaxel. 3. 4.62. TOTAL. 65. 100. Table 3: Relationship between cervical cancer patients' factors and DRPs. Patients Factor. Drug Related Problems (DRPs).

  12. Drug-related problems in patients with osteoporosis

    Directory of Open Access Journals (Sweden)

    Ilić Darko

    2016-01-01

    Full Text Available Background/Aim. Drug-related problems are especially frequent among patients suffering from non-communicable diseases, like osteoporosis, leading to suboptimal treatment response. The aim of this study was to identify drug-related problems in patients with osteoporosis. Methods. This cross-sectional prospective study was conducted in January 2014 on outpatients with osteoporosis from three health facilities in Belgrade, Serbia. The patients included in the study were older than 50 years, and they were offered an anonymous questionnaire with open-ended questions. Results. There were 355 study participants, 329 (92.7% females and 26 (7.3% males. The patients who experienced at least one osteoporotic fracture (n = 208 were significantly less adherent to the therapy, less engaged in sports and regular physical activities, and more prone to nutrition with inadequate intake of calcium and vitamin D than patients without fractures (n = 147. Conclusion. The effectiveness of osteoporosis treatment is decreased by several drug-related problems encountered by both physicians and patients. However, the majority of the drug-related problems could be greatly influenced by appropriate educational programs. [Projekat Ministarstva nauke Republike Srbije, br. 175007

  13. Energy-momentum distribution: A crucial problem in general relativity

    NARCIS (Netherlands)

    Sharif, M.; Fatima, T.

    2005-01-01

    This paper is aimed to elaborate the problem of energy–momentum in general relativity. In this connection, we use the prescriptions of Einstein, Landau–Lifshitz, Papapetrou and Möller to compute the energy–momentum densities for two exact solutions of Einstein field equations. The space–times under

  14. Pharmacist intervention in drug-related problems for patients with ...

    African Journals Online (AJOL)

    Purpose: To investigate the role of the community pharmacist in identifying, preventing and resolving drug related problems (DRPs) encountered by patients, with particular emphasis on cardiovascular drugs in community pharmacies in Northern Cyprus, Turkey. Methods: A prospective observational study for the ...

  15. Factors and Problems Related to Female Genital Mutilation as Seen ...

    African Journals Online (AJOL)

    Objective: To determine the aetiological factors and problems related to female genital mutilation as seen in children at St. Gaspar Hospital. Data source: Secondary data were obtained from St. Gaspar Hospital, records, registers and patients files or case notes from children ward were retrieved and reviewed, later a special ...

  16. The relation of eating problems and amenorrhea in ballet dancers.

    Science.gov (United States)

    Brooks-Gunn, J; Warren, M P; Hamilton, L H

    1987-02-01

    Exercise-induced amenorrhea has received considerable attention in the medical literature. The combination of exercise and low body weight is thought to exert synergistic effects in the pathogenesis of amenorrhea, while the role of dieting and eating problems, another possible causative mechanism, has not been examined. A sample of 55 adult dancers in national and regional classical ballet companies was studied; their mean age was 24.7 yr. Fifty-six percent of the dancers had delayed menarche (age 14 or later) and 19% of the sample were currently amenorrheic (5 months or longer). One-third of the dancers reported having had an eating problem (self-reported anorexia nervosa or bulimia). Amenorrhea and reported eating problems were significantly related: 50% of amenorrheics reported anorexia nervosa while 13% of the normals did. In addition, prolonged amenorrhea was significantly related to dieting (as measured by EAT-26 scales, a measure of dieting behavior). As expected, leanness and absolute weight also were related to prolonged amenorrhea. Amenorrhea in this sample of adult dancers was not related to current activity level or age at which training began. Thus, eating problems may be one factor in the pathogenesis of prolonged amenorrhea in certain athletic groups.

  17. Pharmacists' Intervention to Reduce Drug Related Problems in HIV ...

    African Journals Online (AJOL)

    Despite advances in the use of highly active antiretroviral therapy (HAART) in the management of HIV/AIDS, drug-related problems (DRPs) still remain an issue, particularly in developing countries. This study evaluated the incidence of DRPs among HIV/AIDS patients in a HIV/AIDS care centre in southern Nigeria and the ...

  18. Characteristics of potential drug-related problems among oncology patients

    NARCIS (Netherlands)

    Bulsink, Arjan; Imholz, Alex L. T.; Brouwers, Jacobus R. B. J.; Jansman, Frank G. A.

    Background Oncology patients are more at risk for drug related problems because of treatment with (combinations of) anticancer drugs, as they have a higher risk for organ failure or altered metabolism with progression of their disease. Objective The aim of this study was to characterize and to

  19. Source-to-incident flux relation for a tokamak fusion test reactor blanket module

    International Nuclear Information System (INIS)

    Imel, G.R.

    1982-01-01

    The source-to-incident 14-MeV flux relation for a blanket module on the Tokamak Fusion Test Reactor is derived. It is shown that assumptions can be made that allow an analytical expression to be derived, using point kernel methods. In addition, the effect of a nonuniform source distribution is derived, again by relatively simple point kernel methods. It is thought that the methodology developed is valid for a variety of blanket modules on tokamak reactors

  20. Employers’ View on Problems Related to Workforce Skills and Qualification

    Directory of Open Access Journals (Sweden)

    Klimplová Lenka

    2012-12-01

    Full Text Available The aim of this exploratory study is to reveal employers’ views on problems related to workforce human capital (skills and qualification. Where do employers themselves view the core of difficulties with ensuring adequately skilled workforce? Do they assign them to technological and organizational changes (a functional concept of job-specific human capital obsolescence, or do they see these problems as a result of other circumstances, such as macro-structural conditions or institutional settings? To answer these questions selected employers in mechanical engineering and information technology sectors in the Czech Republic were interviewed. The results show that the employers see the problems: 1 on the side of workforce – insufficient abilities and skills, exaggerated demands and low motivation; 2 as inadequate capacities and capabilities of the organization itself; 3 at macro-level as institutional shortcomings in the initial educational system and social benefits system. The problems related to workforce skills and qualification cannot be, thus, interpreted only in the functionalist view as job-specific human capital obsolescence, but the formulation of the problems is significantly affected by the institutional framework.

  1. Nuclear Security Management for Research Reactors and Related Facilities

    International Nuclear Information System (INIS)

    2016-03-01

    This publication provides a single source guidance to assist those responsible for the implementation of nuclear security measures at research reactors and associated facilities in developing and maintaining an effective and comprehensive programme covering all aspects of nuclear security on the site. It is based on national experience and practices as well as on publications in the field of nuclear management and security. The scope includes security operations, security processes, and security forces and their relationship with the State’s nuclear security regime. The guidance is provided for consideration by States, competent authorities and operators

  2. On the Relationships between (Relatively) Advanced Mathematical Knowledge and (Relatively) Advanced Problem-Solving Behaviours

    Science.gov (United States)

    Koichu, Boris

    2010-01-01

    This article discusses an issue of inserting mathematical knowledge within the problem-solving processes. Relatively advanced mathematical knowledge is defined in terms of "three mathematical worlds"; relatively advanced problem-solving behaviours are defined in terms of taxonomies of "proof schemes" and "heuristic behaviours". The relationships…

  3. Anxiety and health problems related to air travel.

    Science.gov (United States)

    McIntosh, I B; Swanson, V; Power, K G; Raeside, F; Dempster, C

    1998-12-01

    A significant proportion of air travelers experience situational anxiety and physical health problems. Take-off and landing are assumed to be stressful, but anxiety related to other aspects of the air travel process, anxiety coping strategies, and in-flight health problems have not previously been investigated. We aimed to investigate frequency of perceived anxiety at procedural stages of air travel, individual strategies used to reduce such anxiety, and frequency of health problems on short-haul and long-haul flights. A questionnaire measuring the occurrence and frequency of the above was administered to two samples of intending travelers during a 3 month period to: (a) 138 travel agency clients, and (b) 100 individuals attending a hospital travel clinic. Of the 238 respondents, two thirds were women. Take-off and landing were a perceived source of anxiety for about 40% of respondents, flight delays for over 50%, and customs and baggage reclaim for a third of individuals. Most frequent anxiety-reduction methods included alcohol and cigarette use, and distraction or relaxation techniques. Physical health problems related to air travel were common, and there was a strong relationship between such problems and frequency of anxiety. Travel agency clients reported more anxiety but not more physical health symptoms overall than travel clinic clients. Women reported greater air-travel anxiety, and more somatic symptoms than men. Significant numbers of air travelers report perceived anxiety related to aspects of travel, and this is associated with health problems during flights. Airlines and travel companies could institute specific measures, including improved information and communication, to reassure clients and thereby diminish anxiety during stages of air-travel. Medical practitioners and travel agencies should also be aware of the potential stresses of air travel and the need for additional information and advice.

  4. Strategy to identify the causes and to solve a sludge granulation problem in methanogenic reactors: application to a full-scale plant treating cheese wastewater.

    Science.gov (United States)

    Macarie, Hervé; Esquivel, Maricela; Laguna, Acela; Baron, Olivier; El Mamouni, Rachid; Guiot, Serge R; Monroy, Oscar

    2017-08-26

    Granulation of biomass is at the basis of the operation of the most successful anaerobic systems (UASB, EGSB and IC reactors) applied worldwide for wastewater treatment. Despite of decades of studies of the biomass granulation process, it is still not fully understood and controlled. "Degranulation/lack of granulation" is a problem that occurs sometimes in anaerobic systems resulting often in heavy loss of biomass and poor treatment efficiencies or even complete reactor failure. Such a problem occurred in Mexico in two full-scale UASB reactors treating cheese wastewater. A close follow-up of the plant was performed to try to identify the factors responsible for the phenomenon. Basically, the list of possible causes to a granulation problem that were investigated can be classified amongst nutritional, i.e. related to wastewater composition (e.g. deficiency or excess of macronutrients or micronutrients, too high COD proportion due to proteins or volatile fatty acids, high ammonium, sulphate or fat concentrations), operational (excessive loading rate, sub- or over-optimal water upflow velocity) and structural (poor hydraulic design of the plant). Despite of an intensive search, the causes of the granulation problems could not be identified. The present case remains however an example of the strategy that must be followed to identify these causes and could be used as a guide for plant operators or consultants who are confronted with a similar situation independently of the type of wastewater. According to a large literature based on successful experiments at lab scale, an attempt to artificially granulate the industrial reactor biomass through the dosage of a cationic polymer was also tested but equally failed. Instead of promoting granulation, the dosage caused a heavy sludge flotation. This shows that the scaling of such a procedure from lab to real scale cannot be advised right away unless its operability at such a scale can be demonstrated.

  5. Exposure to alcohol advertisements and teenage alcohol-related problems.

    Science.gov (United States)

    Grenard, Jerry L; Dent, Clyde W; Stacy, Alan W

    2013-02-01

    This study used prospective data to test the hypothesis that exposure to alcohol advertising contributes to an increase in underage drinking and that an increase in underage drinking then leads to problems associated with drinking alcohol. A total of 3890 students were surveyed once per year across 4 years from the 7th through the 10th grades. Assessments included several measures of exposure to alcohol advertising, alcohol use, problems related to alcohol use, and a range of covariates, such as age, drinking by peers, drinking by close adults, playing sports, general TV watching, acculturation, parents' jobs, and parents' education. Structural equation modeling of alcohol consumption showed that exposure to alcohol ads and/or liking of those ads in seventh grade were predictive of the latent growth factors for alcohol use (past 30 days and past 6 months) after controlling for covariates. In addition, there was a significant total effect for boys and a significant mediated effect for girls of exposure to alcohol ads and liking of those ads in 7th grade through latent growth factors for alcohol use on alcohol-related problems in 10th grade. Younger adolescents appear to be susceptible to the persuasive messages contained in alcohol commercials broadcast on TV, which sometimes results in a positive affective reaction to the ads. Alcohol ad exposure and the affective reaction to those ads influence some youth to drink more and experience drinking-related problems later in adolescence.

  6. Exposure to Alcohol Advertisements and Teenage Alcohol-Related Problems

    Science.gov (United States)

    Dent, Clyde W.; Stacy, Alan W.

    2013-01-01

    OBJECTIVE: This study used prospective data to test the hypothesis that exposure to alcohol advertising contributes to an increase in underage drinking and that an increase in underage drinking then leads to problems associated with drinking alcohol. METHODS: A total of 3890 students were surveyed once per year across 4 years from the 7th through the 10th grades. Assessments included several measures of exposure to alcohol advertising, alcohol use, problems related to alcohol use, and a range of covariates, such as age, drinking by peers, drinking by close adults, playing sports, general TV watching, acculturation, parents’ jobs, and parents’ education. RESULTS: Structural equation modeling of alcohol consumption showed that exposure to alcohol ads and/or liking of those ads in seventh grade were predictive of the latent growth factors for alcohol use (past 30 days and past 6 months) after controlling for covariates. In addition, there was a significant total effect for boys and a significant mediated effect for girls of exposure to alcohol ads and liking of those ads in 7th grade through latent growth factors for alcohol use on alcohol-related problems in 10th grade. CONCLUSIONS: Younger adolescents appear to be susceptible to the persuasive messages contained in alcohol commercials broadcast on TV, which sometimes results in a positive affective reaction to the ads. Alcohol ad exposure and the affective reaction to those ads influence some youth to drink more and experience drinking-related problems later in adolescence. PMID:23359585

  7. Statistics and Corporate Environmental Management: Relations and Problems

    DEFF Research Database (Denmark)

    Madsen, Henning; Ulhøi, John Parm

    1997-01-01

    Statistical methods have long been used to analyse the macroeconomic consequences of environmentally damaging activities, political actions to control, prevent, or reduce these damages, and environmental problems in the natural environment. Up to now, however, they have had a limited and not very...... specific use in corporate environmental management systems. This paper will address some of the special problems related to the use of statistical techniques in corporate environmental management systems. One important aspect of this is the interaction of internal decisions and activities with conditions...

  8. Job-related doses in light water reactors

    International Nuclear Information System (INIS)

    Schnuer, K.

    1993-01-01

    The Treaty of 1957 establishing the European Atomic Energy Community, (EURATOM) was an essential prerequisite for the development of a strong nuclear industry in Europe. Among other things the Treaty provides that the Community shall lay down Basic Safety Standards for the protection of the health of workers and the general public against the dangers arising from ionizing radiation and ensure that they are applied. Following adoption of the Council Directive of 1980, the European Commission defined the basic principles of Justification, Optimization and Limitation to be applied in order to ensure the greatest possible protection of workers and the general public. Subsequently the Commission took initiatives in order to find ways of implementing these three basic principles in practical radiation protection. In 1980 the Commission in close collaboration with the leading nuclear power station operators, set up its own system of 'occupational radiation dose statistics from light water reactors operating in Western Europe'. This was designed for PWRs and BWRs, and the Commission benefited from the experience of neighbouring non-EC countries such as Sweden, Finland, Switzerland and Spain (not yet a member) operating nuclear power stations made by different manufacturers. The paper provides some general information on developments and trends in collective and individual doses to workers in nuclear power stations, based on a unique European databank of approximately 1000 operating reactor years. 9 figs

  9. Steam explosion - physical foundations and relation to nuclear reactor safety

    International Nuclear Information System (INIS)

    Schumann, U.

    1982-08-01

    'Steam explosion' means the sudden evaporation of a fluid by heat exchange with a hotter material. Other terms are 'vapour explosion', 'thermal explosion', and 'energetic fuel-coolant interaction (FCI)'. In such an event a large fraction of the thermal energy initially stored in the hot material may possibly be converted into mechanical work. For pressurized water reactors one discusses (e.g. in risk analysis studies) a core melt-down accident during which molten fuel comes into contact with water. In the analysis of the consequences one has to investigate steam explosions. In this report an overview over the state of the knowledge is given. The overview is based on an extensive literature review. The objective of the report is to provide the basic knowledge which is required for understanding of the most important theories on the process of steam explosions. Following topics are treated: overview on steam explosion incidents, work potential, spontaneous nucleation, concept of detonation, results of some typical experiments, hydrodynamic fragmentation of drops, bubbles and jets, coarse mixtures, film-boiling, scenario of a core melt-down accident with possible steam-explosion in a pressurized water reactor. (orig.) [de

  10. Improvements in or relating to nuclear fusion reactors

    International Nuclear Information System (INIS)

    Farfaletti-Casali, F.; Peter, F.-G.; Gritzmann, P.G.

    1977-01-01

    An improved modular structure for a hollow toroidal blanket assembly for a thermonuclear reactor is described that is claimed to overcome some of the disadvantages of earlier designs. These disadvantages are discussed. The assembly, for surrounding the plasma cavity of a toroidal reactor, comprises at least two types of annular modules having different cross-sections and internal diameters, and located alternately around the toroidal chamber. Each module is subdivided in the circumferential direction into sub-modules having a uniform cross-section, the small diameter modules tapering towards the outer circumferential side whereas the larger diameter modules taper towards the inner circumferential side. The tapered portions of the modules abut along a circular path surrounding the toroidal cavity, the central axis of which path is displaced radially towards the centre of the toroid. The surfaces of the abutting portions of the smaller diameter modules may be slightly concave, whereas the corresponding portions of the larger diameter modules may be slightly convex. The modules may be provided with cooling means, such as liquid He. At least one type of module may be subdivided into four quadrant sub-modules. (U.K.)

  11. Corrosion problems in the aluminum tank of the reactor of Mexico

    International Nuclear Information System (INIS)

    Mazon, R.

    1995-01-01

    The contention developed a leak that was found on March 15th 1985 in a routine inspection to the exposure room. The maximum water leak reached almost 5 liters per hour, it started to diminish until it disappeared completely two months later. It is believed that the holes were blocked by particles in suspension that were introduced to the primary system during the leaking tests. Immediately after the finding of the leak an inspection, testing and repair program was established. Hydrostatic tests to the primary cooling system and cooling system of the exposure room piping showed that the problem was the aluminum liner and not the piping. In order to have the possibility of inspecting the walls of the tank, the pool was drained from its 7.49 m of water down to 3.6 m of depth. At this point the reactor operation stopped and the inspection work started. Previously gamma radiation doses were evaluated using TLD crystals and was determined that 3.6 m of water column gave 0.1 mR/hr of gamma radiation doses at the surface. (orig./HP)

  12. The Paucity Problem: Where Have All the Space Reactor Experiments Gone?

    Energy Technology Data Exchange (ETDEWEB)

    Bess, John D.; Marshall, Margaret A.

    2016-10-01

    The Handbooks of the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and the International Reactor Physics Experiment Evaluation Project (IRPhEP) together contain a plethora of documented and evaluated experiments essential in the validation of nuclear data, neutronics codes, and modeling of various nuclear systems. Unfortunately, only a minute selection of handbook data (twelve evaluations) are of actual experimental facilities and mockups designed specifically for space nuclear research. There is a paucity problem, such that the multitude of space nuclear experimental activities performed in the past several decades have yet to be recovered and made available in such detail that the international community could benefit from these valuable historical research efforts. Those experiments represent extensive investments in infrastructure, expertise, and cost, as well as constitute significantly valuable resources of data supporting past, present, and future research activities. The ICSBEP and IRPhEP were established to identify and verify comprehensive sets of benchmark data; evaluate the data, including quantification of biases and uncertainties; compile the data and calculations in a standardized format; and formally document the effort into a single source of verified benchmark data. See full abstract in attached document.

  13. Dissolved nitrogen in liquid lithium - a problem in fusion reactor chemistry

    International Nuclear Information System (INIS)

    Hubberstey, P.

    1984-01-01

    When dissolved in liquid lithium, nitrogen adopts the role filled by oxygen in liquid sodium systems, reacting readily with stainless steel containment materials to form Li 9 CrN 5 as a surface product; extended reaction leads to pronounced corrosion and embrittlement problems. It also interacts with both carbon and silicon impurities forming Li 2 NCN and Li 5 SiN 3 , respectively; it is inert, however, to oxygen impurity. Although dissolved nitrogen reacts with neither the tritium generated in the breeding process nor the lead added to act as a neutron multiplier, its presence may seriously influence tritium recovery processes since it reacts with and hence may poison the majority of the transition metals (Y,Ti,Zr) presently being considered as tritium getter materials. Its reactivity with these metals forms the basis of the hot trapping technique used to remove dissolved nitrogen from liquid lithium systems; cold trapping is ineffective because of its large solubility even at temperatures just above the melting point of pure lithium (453.6K). Whenever possible, the chemistry of nitrogen dissolved in liquid lithium is rationalised using the thermodynamic concepts and its significance to fusion reactor technology stressed. (author)

  14. Study of MHD problems in liquid metal blankets of fusion reactors

    International Nuclear Information System (INIS)

    Michael, I.

    1984-12-01

    This study describes in a concise form the state of knowledge regarding MHD problems to be expected in case of use of liquid metal in the blankets of fusion reactors with magnetic confinement. MHD pressure losses and MHD friction coefficients in the straight channel, in bent sections and in case of variation of the channel cross section play a major role because the high MHD flow resistances call for high pumping powers. Influencing the velocity profile transverse to the main flow direction of the liquid metal by application of an external, strong magnetic field bears consequences on the release and transport of corrosion products in the liquid metal circuit and on the heat transfer. Possibilities of reducing the MHD effects are discussed. However, it becomes obvious that an account of the lack of experimental results there are still major gaps in the knowledge of MHD effects occurring in strong magnetic fields. These gaps can be greatly reduced by implementation of an experimental program as proposed in this report. (orig.) [de

  15. Some problems of solar-terrestrial energy relations

    International Nuclear Information System (INIS)

    Kovalevskij, I.V.

    1982-01-01

    Energy aspects of relations of phenomena occurring on the Sun, in the interplanetary space, magnetosphere, ionosphere and on the Earth's surface are discussed. Particular attention is given to the energy radiated by the Sun (flares, coronal holes). The problems are considered of the energy transfer and transformation in high-velocity and flare flows of solar wind. Estimates are performed: of densities of various types of energy of the interplanetary space at the Earth's orbit level; energy fluxes incident on the magnetosphere; energy accumulated inside the magnetosphere; a series of energy parameters of magnetic storms. It is pointed out that nowadays one of the main problems of the magnetosphere physics is studying ways of the interplanatary space energy transfer into the magnetosphere. In this connection some problems are investigated: plasma penetration through the dayside magnetopause, solar wind plasma entry into the magnetotail, the electric field effect on transition region plasma penetration into the distant magnetotail

  16. State Confessional Relations: Problem of the Subject Structure

    Directory of Open Access Journals (Sweden)

    Alexandra A. Dorskaya

    2014-06-01

    Full Text Available In the article various existing definitions of the concept "state and confessional relations" are analyzed, also author's definition is offered. Three levels of the state and confessional relations are revealed: conceptual, legislative and administrative-managerial. In the article it is shown that in Russia a tradition of only two subjects of the state and confessional relations – government bodies and the religious organizations allocation exists. It is revealed that at the present stage many researchers are dissatisfied with such situation. Scientific sources of the problem of the state and church relations within the psychological school of the law, which are addressed to the personality and experiences in the legal sphere are studied and revealed. Special attention is paid to scientific heritage of the M.A. Reysner, who was one of the first to begin study of this problem. In the article the question of the school of three subjects of the state and confessional relations allocation formation, what adds the faithful or faithless personality in addition to two traditional subjects is analyzed. The state and confessional relations are considered in the context of the human rights development. The question of new type of the believer possessing high education level and knowledge formation is considered. In the article it is shown that at the present stage relations of any regulation between the state and religious organizations is based on the basis of international legal standards, domestic legislation and norms of canon law.

  17. Public acceptance and public relations. Communication approach to related pre-public relation problems

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Y [Gakushuin Univ., Tokyo (Japan)

    1977-07-01

    A set of problems are discussed, which must be studied before the public relations are dealt with. Firstly, the trade-off between energy and health must be considered. Although the probability of death caused by atomic accidents is very small (one three hundred millionth a year), many peoples hate atomic power and oppose to the construction of nuclear power plants. Four reasons for this are considered: (1) social diffusion of innovation, (2) nuclear allergy, (3) shortage of the conception of risk-benefit, and (4) heterogeneity of the public. According to the investigation of the relationship between electric power and livelihood, carried out by the policyand science research institute in Tokyo, the highly subjective decision for the acceptance of atomic power is independent of the objective knowledge on atomic power.

  18. Research reactors. Problems of fuel element enrichment reduction. Deliberations and comments

    International Nuclear Information System (INIS)

    1978-10-01

    This paper summarises the main data from the major research reactors in the Federal Republic of Germany utilising highly enriched uranium (HEU) and presently available fuel technology for their fuel elements. The required modification for an adaption of the fabrication to lower enriched fuel are considered as well as the consequences on reactor performance operation and licensing. On the basis of past experience with reactor modifications a rough estimate of 82 months is given for the conversion of a reactor to a modified type of fuel and of 70 months for a fuel test program. The conclusions reflect the own calculations and data from other papers submitted to INFCE-WG 8C

  19. High efficiency algorithm for 3D transient thermo-elasto-plastic contact problem in reactor pressure vessel sealing system

    International Nuclear Information System (INIS)

    Xu Mingyu; Lin Tengjiao; Li Runfang; Du Xuesong; Li Shuian; Yang Yu

    2005-01-01

    There are some complex operating cases such as high temperature and high pressure during the operating process of nuclear reactor pressure vessel. It is necessary to carry out mechanical analysis and experimental investigation for its sealing ability. On the basis of the self-developed program for 3-D transient sealing analysis for nuclear reactor pressure vessel, some specific measures are presented to enhance the calculation efficiency in several aspects such as the non-linear solution of elasto-plastic problem, the mixed solution algorithm for contact problem as well as contract heat transfer problem and linear equation set solver. The 3-D transient sealing analysis program is amended and complemented, with which the sealing analysis result of the pressure vessel model can be obtained. The calculation results have good regularity and the calculation efficiency is twice more than before. (authors)

  20. Sleep-related problems in common medical conditions.

    Science.gov (United States)

    Parish, James M

    2009-02-01

    Common medical problems are often associated with abnormalities of sleep. Patients with chronic medical disorders often have fewer hours of sleep and less restorative sleep compared to healthy individuals, and this poor sleep may worsen the subjective symptoms of the disorder. Individuals with lung disease often have disturbed sleep related to oxygen desaturations, coughing, or dyspnea. Both obstructive lung disease and restrictive lung diseases are associated with poor quality sleep. Awakenings from sleep are common in untreated or undertreated asthma, and cause sleep disruption. Gastroesophageal reflux is a major cause of disrupted sleep due to awakenings from heartburn, dyspepsia, acid brash, coughing, or choking. Patients with chronic renal disease commonly have sleep complaints often due to insomnia, insufficient sleep, sleep apnea, or restless legs syndrome. Complaints related to sleep are very common in patients with fibromyalgia and other causes of chronic pain. Sleep disruption increases the sensation of pain and decreases quality of life. Patients with infectious diseases, including acute viral illnesses, HIV-related disease, and Lyme disease, may have significant problems with insomnia and hypersomnolence. Women with menopause have from insomnia, sleep-disordered breathing, restless legs syndrome, or fibromyalgia. Patients with cancer or receiving cancer therapy are often bothered by insomnia or other sleep disturbances that affect quality of life and daytime energy. The objective of this article is to review frequently encountered medical conditions and examine their impact on sleep, and to review frequent sleep-related problems associated with these common medical conditions.

  1. A new evolutionary algorithm with LVQ learning for the optimization of combinatory problems as a reload of nuclear reactors

    International Nuclear Information System (INIS)

    Machado, Marcelo Dornellas

    1999-04-01

    Genetic algorithms are biologically motivated adaptive systems which have been used, with good results, for function optimization. In this work, a new learning mode, to be used by the Population-Based Incremental Learning (PBIL) algorithm, who combines mechanisms of standard genetic algorithm with simple competitive learning, has the aim to build a new evolutionary algorithm to be used in optimization of numerical problems and combinatorial problems. This new learning mode uses a variable learning rate during the optimization process, constituting a process know as proportional reward. The development of this new algorithm aims its application in the optimization of reload problem of PWR nuclear reactors. This problem can be interpreted as search of a load pattern to be used in the nucleus of the reactor in order to increase the useful life of the nuclear fuel. For the test, two classes of problems are used: numerical problems and combinatorial problem, the major interest relies on the last class. The results achieved with the tests indicate the applicability of the new learning mode, showing its potential as a developing tool in the solution of reload problem. (author)

  2. Experience in settlement analysis and related geostatic considerations for the foundation design of heavy reactor structures

    International Nuclear Information System (INIS)

    McNeill, R.L.; Yen, B.C.; Bhushan, K.; Haley, S.C.

    1976-01-01

    Potential settlement problems associated with new, heavier reactor structures are discussed. Methods for obtaining data for settlement analyses are summarized and analysis procedures are compared in an example. Stress history and stress distribution concepts are shown to be important for settlement estimates. (author)

  3. Reactor physics experiments related to transmutation in the KUCA

    Energy Technology Data Exchange (ETDEWEB)

    Shiroya, Seiji [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.

    1997-11-01

    At the Kyoto University Critical Assembly (KUCA), {sup 237}Np/{sup 235}U fission rate ratios are being measured using the back-to-back type double fission chamber to examine the nuclear data and the computational method for the transmutation of minor actinides (MA) in light water reactors (LWRs). The neutron spectra of cores are systematically being varied by changing the moderator-to-fuel volume ratio (V{sub m}/V{sub f}). The measured data are being compared with the calculated results by SRAC with three different nuclear data files. It has been indicated that the calculated results with JENDL-3.2 agreed better with the measured ones than those with JENDL-3.1 and ENDF/B-VI, although the calculated results underestimated the measured ones by around 10%. (author)

  4. Study of reactor analysis codes available at IPEN and their application to problems involving the diffusion theory

    International Nuclear Information System (INIS)

    Mendonca, A.G.

    1980-01-01

    Two computer codes that are available at IPEN for analyses of static neutron diffusion problems are studied and applied. The CITATION code is animed at analyses of criticality, fuel burnup, flux and power distributions etc, in one, two, and three spatial dimensions in multigroup. The EXTERMINATOR code can be used for the same purposes as for CITATION with a limitation to one or two spatial dimensions. Basic theories and numerical techniques used in the codes are studied and summarized. Benchmark problems have been solved using the codes. Comparisons of the results show that both codes can be used with confidence in the analyses of nuclear reactor problems. (author) [pt

  5. The problem of time quantum mechanics versus general relativity

    CERN Document Server

    Anderson, Edward

    2017-01-01

    This book is a treatise on time and on background independence in physics. It first considers how time is conceived of in each accepted paradigm of physics: Newtonian, special relativity, quantum mechanics (QM) and general relativity (GR). Substantial differences are moreover uncovered between what is meant by time in QM and in GR. These differences jointly source the Problem of Time: Nine interlinked facets which arise upon attempting concurrent treatment of the QM and GR paradigms, as is required in particular for a background independent theory of quantum gravity. A sizeable proportion of current quantum gravity programs - e.g. geometrodynamical and loop quantum gravity approaches to quantum GR, quantum cosmology, supergravity and M-theory - are background independent in this sense. This book's foundational topic is thus furthermore of practical relevance in the ongoing development of quantum gravity programs. This book shows moreover that eight of the nine facets of the Problem of Time already occur upon ...

  6. Report on safety related occurrences and reactor trips July 1, 1977 - December 31, 1977

    International Nuclear Information System (INIS)

    Andermo, L.; Sundman, B.

    1974-04-01

    This is a systematically arranged report on all reported safety related occurrences and reactor trips in Swedish nuclear power plants in operation during July 1 to December 31, 1977 inclusive. The facilities involved are Barsebaeck 1 and 2, Oskarshamn 1 and 2 and Ringhals 1 and 2. During this period of 6 months 48 safety related occurrences and 49 reactor trips have been reported to the Nuclear Power Inspectorate. Included is also one incident June 21 in Barsebaeck 2 which was not included in the last compilation of occurrences. As earlier experiences have shown it is to the greatest extent the conventional components which bring about the safety related occurrences or occurrences leading to outages or power reductions. However, the component errors discovered in the safety related systems have not affected the function of their redundant systems and other diverse systems have not been involved. Therefore the reactor safety has been satisfactory. The total number of reactor trips have increased nearly 30% since the last period. Those occurred during power operation however, were less. More than 50% of the reactor trips happened in the shutdown condition. The fact that even small deviations from prescribed operation result in automatic and safe shut down of the reactor, does not always imply a conflict with operational availability. The greatest outages are caused by occurrences withou02068NRM 0000169 450

  7. Report on safety related occurrences and reactor trips July 1, 1979 - December 31, 1979

    International Nuclear Information System (INIS)

    Olsson, S.; Andermo, L.

    1980-01-01

    This is a report on all reported safety related occurrences and reactor trips in Swedish nuclear power plants in operation during July 1 to December 31, 1979 inclusive. The facilities involved are Barsebaeck 1 and 2, Oskarshamn 1 and 2 and Ringhals 1 and 2. During this period of 6 months 76 safety related occurrences and 27 reactor trips have been reported to the Nuclear Power Inspectorate. It is to the greatest extent conventional components such as valves and pumps which bring about the safety related occurrences or occurrences leading to outages or power reductions. However, the component errors discovered in the safety related systems have not affected the function of their redundant system and other diverse systems have not been involved. Therefore the reactor safety has been satisfactory. The total number of reactor trips are normal. The average value for these 6 months is 4.5 trips/unit. Approximetely one half of the reactor trips happened at zero or very low power operation. The fact that even small deviations from prescribed operation result in an automatic and safe shut down of the reactor, does not always imply a conflict with operational availability. The greatest outages are caused by occurrences without safety significance. (author)

  8. Ear-related problems among children attending the paediatric and ...

    African Journals Online (AJOL)

    2006-08-31

    Aug 31, 2006 ... Results: Three thousand and twenty-one children were seen during the study period. Out of these, 248 children (8.2%) pre- sented with ear-related problems. Chronic otitis media (30.5%), acute otitis media (29.9%), cerumen auris (11.3%), otitis ex- terna(10.1%), hearing impairment (7.3%) and foreign body ...

  9. Recent progress in safety-related applications of reactor noise analysis

    International Nuclear Information System (INIS)

    Hirota, Jitsuya; Shinohara, Yoshikuni; Saito, Keiichi

    1982-01-01

    Recent progress in safety-related applications of reactor noise analysis is reviewed, mainly referring to various papers presented at the Third Specialists' Meeting on Reactor Noise (SMORN-III) held in Tokyo in 1981. Advances in application of autoregressive model, coherence analysis and pattern recognition technique are significant since SMORN-II in 1977. Development of reactor diagnosis systems based on noise analysis is in progress. Practical experiences in the safety-related applications to power plants are being accumulated. Advances in quantitative monitoring of vibration of internal structures in PWR and diagnosis of core stability and control system characteristics in BWR are notable. Acoustic methods are also improved to detect sodium boiling in LMFBR. The Reactor Noise Analysis Benchmark Test performed by Japan in connection with SMORN-III is successful so that it is possible to proceed to the second stage of the benchmark test. (author)

  10. Problem solving of student with visual impairment related to mathematical literacy problem

    Science.gov (United States)

    Pratama, A. R.; Saputro, D. R. S.; Riyadi

    2018-04-01

    The student with visual impairment, total blind category depends on the sense of touch and hearing in obtaining information. In fact, the two senses can receive information less than 20%. Thus, students with visual impairment of the total blind categories in the learning process must have difficulty, including learning mathematics. This study aims to describe the problem-solving process of the student with visual impairment, total blind category on mathematical literacy issues based on Polya phase. This research using test method similar problems mathematical literacy in PISA and in-depth interviews. The subject of this study was a student with visual impairment, total blind category. Based on the result of the research, problem-solving related to mathematical literacy based on Polya phase is quite good. In the phase of understanding the problem, the student read about twice by brushing the text and assisted with information through hearing three times. The student with visual impairment in problem-solving based on the Polya phase, devising a plan by summoning knowledge and experience gained previously. At the phase of carrying out the plan, students with visual impairment implement the plan in accordance with pre-made. In the looking back phase, students with visual impairment need to check the answers three times but have not been able to find a way.

  11. Reactor oscillator project - Theoretical study; operation problems; choice of the ionization chamber

    International Nuclear Information System (INIS)

    Lolic, B.; Markovic, V.

    1961-01-01

    Theoretical study of the reactor operator covers methods of the danger coefficient and the method based on measuring the phase angle. Operation with the reactor oscillator describes measurement of the cross section and resonance integral, measurement of the fissionable materials properties, measurement of impurities in the graphite sample. A separate chapter is devoted to the choice of the appropriate ionization chamber

  12. To the problem of regulating of software applicability for the analysis of domestic reactor accidents

    International Nuclear Information System (INIS)

    Kim, V.V.; Skalozubov, V.I.

    1999-01-01

    Based on consideration and generalization of results of verification/validation researches the necessity of development of an objective evaluation criterions of software applicability (calculated codes) for separate types of domestic reactor accidents is justified. These criterions should be used in a normative position of certification or the application order of calculated codes for the analysis of reactor safety

  13. Terrorism-related trauma in Africa, an increasing problem.

    Science.gov (United States)

    Alfa-Wali, Maryam; Sritharan, Kaji; Mehes, Mira; Abdullah, Fizan; Rasheed, Shahnawaz

    2015-06-01

    Global terrorist activities have increased significantly over the past decade. The impact of terrorism-related trauma on the health of individuals in low- and middle-income countries is under-reported. Trauma management in African countries in particular is uncoordinated, with little or no infrastructure to cater for emergency surgical needs. This article highlights the need for education, training and research to mitigate the problems related to terrorism and surgical public health. Copyright © 2014 Ministry of Health, Saudi Arabia. Published by Elsevier Ltd. All rights reserved.

  14. Changing concepts of geologic structure and the problem of siting nuclear reactors: examples from Washington State

    International Nuclear Information System (INIS)

    Tabor, R.W.

    1986-01-01

    The conflict between regulation and healthy evolution of geological science has contributed to the difficulties of siting nuclear reactors. On the Columbia Plateau in Washington, but for conservative design of the Hanford reactor facility, the recognition of the little-understood Olympic-Wallowa lineament as a major, possibly still active structural alignment might have jeopardized the acceptability of the site for nuclear reactors. On the Olympic Peninsula, evolving concepts of compressive structures and their possible recent activity and the current recognition of a subducting Juan de Fuca plate and its potential for generating great earthquakes - both concepts little-considered during initial site selection - may delay final acceptance of the Satsop site. Conflicts of this sort are inevitable but can be accommodated if they are anticipated in the reactor-licensing process. More important, society should be increasing its store of geologic knowledge now, during the current recess in nuclear reactor siting

  15. The Fertility Problem Inventory: measuring perceived infertility-related stress.

    Science.gov (United States)

    Newton, C R; Sherrard, W; Glavac, I

    1999-07-01

    To develop a reliable, valid instrument to evaluate perceived infertility-related stress. Prospective study. University-affiliated teaching hospital. Consecutively referred patients (1,153 women and 1,149 men) seen for infertility treatment. None. Participants' infertility-related stress was assessed by written questionnaire using the Fertility Problem Inventory. Current levels of anxiety, depression, and marital satisfaction also were determined. Women described greater global stress than men and higher specific stress in terms of social concerns, sexual concerns, and need for parenthood. Both men and women facing male infertility reported higher global stress and more social and sexual concerns than men and women experiencing female infertility. Social, sexual, and relationship concerns related to infertility were more effective predictors of depression and marital dissatisfaction than expressed needs for parenthood or attitudes toward child-free living. The Fertility Problem Inventory provides a reliable measure of perceived infertility-related stress and specific information on five separate domains of patient concern. Patterns of infertility-related stress differed depending on gender, fertility history, and infertility diagnosis. Among patients receiving treatment, social, sexual, and relationship concerns appear central to current distress. Counseling interventions that target these domains appear likely to offer maximal therapeutic benefit.

  16. U.S. activities related to fast reactors and ADS

    International Nuclear Information System (INIS)

    Finck, Phillip J.

    2001-01-01

    The U.S. nuclear power industry achieved its second straight year of record power generation levels during 2000. Total power generated was 753.9 billion kWh, 3.5 percent above the previous record of 728.1 billion kWh set in 1999. Recent years of reliable service and declining production costs have led to increased industry interest in nuclear power plant license renewal. The Nuclear Regulatory Commission approved the license renewal applications for five U.S. nuclear power plants in 2000. Five additional applications were received and 28 more are planned to be submitted by 2004. Concerns over energy resource availability, climate change, air quality, and energy security suggest an important role for nuclear power in future energy supplies. While the current Generation II and III nuclear power plant designs provide an economically, technically, and publicly acceptable electricity supply in many markets, further advances in nuclear energy system design can broaden the opportunities for the use of nuclear energy. To explore these opportunities, the U. S. Department of Energy's Office of Nuclear Energy, Science and Technology has engaged governments, industry, and the research community worldwide in a wide-ranging discussion on the development of next-generation nuclear energy systems known as 'Generation IV'. The I-NERI program has the following objectives: Develop advanced concepts and scientific breakthroughs in nuclear fission and reactor technology to address and overcome the principal technical and scientific obstacles to the expanded use of nuclear energy worldwide; Promote bilateral and multilateral collaboration with international agencies and research organizations to improve development of nuclear energy; and Promote and maintain nuclear science and engineering infrastructure to meet future technical challenges. I-NERI will sponsor innovative research and development in the following areas: Next-generation nuclear energy plant designs with higher efficiency

  17. Some geomedical problems in relation to soil science

    International Nuclear Information System (INIS)

    Laag, J.

    1988-01-01

    Geomedicine may be defined as the science dealing with the influence of ordinary environmental factors on geographical distribution of health problems in man and animals. An important group of geomedical problems is connected to nutrition. These problems may either be caused by deficiency or surplus of certain matters. Many questions concerning the pollution of nature are classified under the latter group Radioactive pollutants are regarded as important special occurrences under this group. In order to be able to solve complicated geomedical problems, knowledge is needed on the circulation processes rocks-soils-water-plants-animals-man, and waste products back to the soils. The registration of locations of different radioactive elements can give basic material for special geomedical conclusions. Many chemical reactions in which radioactive matter are involved, depend on properties of the soils. Humus and clay minerals have, generally speaking, a high capacity for the absorbtion of soluble matter, but great variations occur. The reactions of radioactive isotopes supplied from the atmosphere, depend on properties of the soil. Radioactive substances are leached relatively rapidly from a soil with low absorption capacity, and may thus be taken away from the circulation in which terrestrial plants, animals and man take part. If the substances is strongly absorbed (fixed), they can also to some extent be withdrawn from the circulation processes

  18. Problems in calculating reactor model (primary circuit) for nuclear power plant diagnostics

    International Nuclear Information System (INIS)

    Markov, P.

    1986-01-01

    Some results are presented of the calculation of eigen-vibrations of the system of WWER-440 nuclear reactor vessels in a vacuum and in a liquid. Computer code BOSOR 4 has been written for calculating forced vibrations of shells with axial symmetry and of a simplified system of reactor vessels. A description is given of this code, which is based on the so-called energy method of finite differences. Briefly discussed is the feasibility of applying the results of the latest computation techniques in the diagnostics of the major components of a nuclear reactor. (Z.M.)

  19. The problem of a digital simulation of Xe oscillations in power reactors

    International Nuclear Information System (INIS)

    Elzmann, H.J.

    1974-04-01

    Xe-induced power oscillations are simulated in a pressurized water reactor. The coupled balance equation for the neutrons and the decay products iodine/xenon are decoupled via a quasi-stationary approach. The stationary multigroup diffusion equation is solved with a difference method. The whole model is realized with the aid of already existing modules of the reactor program system RSYST. Its basic usefulness is established. A further expansion of the method is discussed with the aim to develop rod drive programs for real reactors. (orig./LN) [de

  20. Survey of the results of a two- and three-dimensional kinetics benchmark problem typical for a thermal reactor

    International Nuclear Information System (INIS)

    Werner, W.

    1975-01-01

    In 1973, NEACRP and CSNI posed a number of kinetic benchmark problems intended to be solved by different groups. Comparison of the submitted results should lead to estimates on the accuracy and efficiency of the employed codes. This was felt to be of great value since the codes involved become more and more important in the field of reactor safety. In this paper the results of the 2d and 3d benchmark problem for a BWR are presented. The specification of the problem is included in the appendix of this survey. For the 2d benchmark problem, 5 contributions have been obtained, while for the 3d benchmark problem 2 contributions have been submitted. (orig./RW) [de

  1. Development of a multi-objective PBIL evolutionary algorithm applied to a nuclear reactor core reload optimization problem

    International Nuclear Information System (INIS)

    Machado, Marcelo D.; Dchirru, Roberto

    2005-01-01

    The nuclear reactor core reload optimization problem consists in finding a pattern of partially burned-up and fresh fuels that optimizes the plant's next operation cycle. This optimization problem has been traditionally solved using an expert's knowledge, but recently artificial intelligence techniques have also been applied successfully. The artificial intelligence optimization techniques generally have a single objective. However, most real-world engineering problems, including nuclear core reload optimization, have more than one objective (multi-objective) and these objectives are usually conflicting. The aim of this work is to develop a tool to solve multi-objective problems based on the Population-Based Incremental Learning (PBIL) algorithm. The new tool is applied to solve the Angra 1 PWR core reload optimization problem with the purpose of creating a Pareto surface, so that a pattern selected from this surface can be applied for the plant's next operation cycle. (author)

  2. NJOY-97, General ENDF/B Processing System for Reactor Design Problems

    International Nuclear Information System (INIS)

    1999-01-01

    1 - Description of program or function: The NJOY nuclear data processing system is a modular computer code used for converting evaluated nuclear data in the ENDF format into libraries useful for applications calculations. Because the Evaluated Nuclear Data File (ENDF) format is used all around the world (e.g., ENDF/B-VI in the US, JEF-2.2 in Europe, JENDL-3.2 in Japan, BROND-2.2 in Russia), NJOY gives its users access to a wide variety of the most up-to-date nuclear data. NJOY provides comprehensive capabilities for processing evaluated data, and it can serve applications ranging from continuous-energy Monte Carlo (MCNP), through deterministic transport codes (DANT, ANISN, DORT), to reactor lattice codes (WIMS, EPRI). NJOY handles a wide variety of nuclear effects, including resonances, Doppler broadening, heating (KERMA), radiation-damage, thermal scattering (even cold moderators), gas production, neutrons and charged particles, photo-atomic interactions, self shielding, probability tables, photon production, and high-energy interactions (to 150 MeV). Output can include printed listings, special library files for applications, and Postscript graphics (plus colour). More information on NJOY is available from the developer's home page at http://t2.lanl.gov. Follow the Tourbus section of the Tour area to find notes from the ICTP lectures held at Trieste in March 1998 on the ENDF format and on the NJOY code. 2 - Methods: NJOY97 consists of a set of modules, each performing a well-defined processing task. Each of these modules is essentially a separate computer program linked together by input and output files and a few common constants. The methods and instructions on how to use them are documented in the LA-12740-M report on NJOY91 and in the 'README' file. No new published document is yet available. NJOY97 is a cleaned up version of NJOY94.105 that features compatibility with a wider variety of compilers and machines, explicit double precision for 32-bit systems, a

  3. Assessment of computational fluid dynamics (CFD) for nuclear reactor safety problems

    International Nuclear Information System (INIS)

    Smith, B. L.; Andreani, M.; Bieder, U.; Bestion, D.; Ducros, F.; Graffard, E.; Heitsch, M.; Scheuerer, M.; Henriksson, M.; Hoehne, T.; Rohde, U.; Lucas, D.; Komen, E.; Houkema, M.; Mahaffy, J.; Moretti, F.; Morii, T.; Muehlbauer, P.; Song, C.H.; Zigh, G.; Menter, F.; Watanabe, T.

    2008-01-01

    The basic objective of the present work was to provide documented evidence of the need to perform CFD simulations in Nuclear Reactor Safety (NRS), concentrating on single-phase applications, and to assess the competence of the present generation of CFD codes to perform these simulations reliably. The fulfilling of this objective involves multiple tasks, summarized as: to provide a classification of NRS problems requiring CFD analysis, to identify and catalogue existing CFD assessment bases, to identify shortcomings in CFD approaches, to put into place a means for extending the CFD assessment database, with an emphasis on NRS applications. The resulting document is presented here. After some introductory remarks, chapter 3 lists twenty-two NRS issues for which it is considered that the application of CFD would bring real benefits in terms of better predictive capability. This classification is followed by a short description of the safety issue, a state-of-the-art summary of what has been attempted, and what is still needed to be done to improve reliability. Chapter 4 details the assessment bases that have already been established in both the nuclear and non-nuclear domains, and discusses the usefulness and relevance of the work to NRS applications, where appropriate. This information is augmented in Chapter 5 by descriptions of the existing CFD assessment bases that have been established around specific, NRS problems. Typical examples are experiments devoted to the boron dilution issue, pressurised thermal shock, and thermal fatigue in pipes. Chapter 6 is devoted to identifying the technology gaps which need to be closed to make CFD a more trustworthy analytical tool. Some deficiencies identified are lack of a Phenomenon Identification and Ranking Table (PIRT), limitations in the range of application of turbulence models, coupling of CFD with neutronics and system codes, and computer power limitations. Most CFD codes currently being used have their own, custom

  4. Validation of the AZTRAN 1.1 code with problems Benchmark of LWR reactors; Validacion del codigo AZTRAN 1.1 con problemas Benchmark de reactores LWR

    Energy Technology Data Exchange (ETDEWEB)

    Vallejo Q, J. A.; Bastida O, G. E.; Francois L, J. L. [UNAM, Facultad de Ingenieria, Departamento de Sistemas Energeticos, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Xolocostli M, J. V.; Gomez T, A. M., E-mail: amhed.jvq@gmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2016-09-15

    The AZTRAN module is a computational program that is part of the AZTLAN platform (Mexican modeling platform for the analysis and design of nuclear reactors) and that solves the neutron transport equation in 3-dimensional using the discrete ordinates method S{sub N}, steady state and Cartesian geometry. As part of the activities of Working Group 4 (users group) of the AZTLAN project, this work validates the AZTRAN code using the 2002 Yamamoto Benchmark for LWR reactors. For comparison, the commercial code CASMO-4 and the free code Serpent-2 are used; in addition, the results are compared with the data obtained from an article of the PHYSOR 2002 conference. The Benchmark consists of a fuel pin, two UO{sub 2} cells and two other of MOX cells; there is a problem of each cell for each type of reactor PWR and BWR. Although the AZTRAN code is at an early stage of development, the results obtained are encouraging and close to those reported with other internationally accepted codes and methodologies. (Author)

  5. Method and codes for solving the optimization problem of initial material distribution and controlling of reactor during the run

    International Nuclear Information System (INIS)

    Isakova, L.Ya.; Rachkova, D.A.; Vtorova, O.Yu.; Matekin, M.P.; Sobol, I.M.

    1992-01-01

    The optimization problem of initial distribution of fuel composition and controlling of the reactor during the run is solved. The optimization problem is formulated as a multicriterial one with different types of constraints. The distinguished feature of the method proposed is the systematic scanning of multidimensional ares, where the trial points in the space of parameters are the points of uniformly distributed LP τ -sequences. The reactor computation is carried out by the four group diffusion method in two-dimensional cylindrical geometry. The burnup absorbers are taken into account as additional absorption cross-sections, represented by approximants. The tables of trials make possible the estimation of the values of global extrema. The coordinates of the points where the external values are attained can be estimated too

  6. Cuckoo Search with flight of Levy applied to the problem of reload of fuels in nuclear reactors

    International Nuclear Information System (INIS)

    Silva, Patrick V.; Nast, Fernando N.; Schirru, Roberto; Meneses, Anderson A.M.; Coordenacao de Pos-Graduacao e Pesquisa de Engenharia

    2017-01-01

    Intra-Nuclear Fuel Management Optimization is a complex combinatorial problem of the NP-difficult type, associated with the refueling process of a nuclear reactor, which aims to extend the cycle of operation by determining loading patterns, obeying safety margins. In addition to the combinatorial problem, we have the aspect of calculations of reactor physics, which increases the difficult of OGCIN. Methods that are proving effective when applied to OGCIN are the algorithms belonging to the swarm intelligence paradigm. A new member of this paradigm is Cuckoo Search (CS), which has shown results promising when applied to optimization issues. The CS is based on the litter parasitism of some cuckoo species combined with the Levy flight behavior of some birds. In the present work we present the results of the application of CS to OGCIN, and compare them to the results obtained by the application of ABC

  7. Comparative analysis of results between CASMO, MCNP and Serpent for a suite of Benchmark problems on BWR reactors

    International Nuclear Information System (INIS)

    Xolocostli M, J. V.; Vargas E, S.; Gomez T, A. M.; Reyes F, M. del C.; Del Valle G, E.

    2014-10-01

    In this paper a comparison is made in analyzing the suite of Benchmark problems for reactors type BWR between CASMO-4, MCNP6 and Serpent code. The Benchmark problem consists of two different geometries: a fuel cell of a pin and assembly type BWR. To facilitate the study of reactors physics in the fuel pin their nuclear characteristics are provided to detail, such as burnt dependence, the reactivity of selected nuclide, etc. With respect to the fuel assembly, the presented results are regarding to infinite multiplication factor for burning different steps and different vacuum conditions. Making the analysis of this set of Benchmark problems provides comprehensive test problems for the next fuels generation of BWR reactors with high extended burned. It is important to note that when making this comparison the purpose is to validate the methodologies used in modeling for different operating conditions, if the case is of other BWR assembly. The results will be within a range with some uncertainty, considering that does not depend on code that is used. Escuela Superior de Fisica y Matematicas of Instituto Politecnico Nacional (IPN (Mexico) has accumulated some experience in using Serpent, due to the potential of this code over other commercial codes such as CASMO and MCNP. The obtained results for the infinite multiplication factor are encouraging and motivate the studies to continue with the generation of the X S of a core to a next step a respective nuclear data library is constructed and this can be used by codes developed as part of the development project of the Mexican Analysis Platform of Nuclear Reactors AZTLAN. (Author)

  8. Contraction of information and its inverse problem in reactor system identification and stochastic diagnosis

    International Nuclear Information System (INIS)

    Kishida, K.

    1996-01-01

    Research concerning power reactor noise analysis makes rapid progress in the areas of the system identification, prediction and diagnosis. Keywords in these studies are artificial intelligence, neural network, fuzzy, and chaos. Nonlinear, nonstationary, or non-Gaussian processes as well as linear and steady processes are also studied in fluctuation analysis. However, we have not enough time to study a fundamental theory, since we are urged to obtain results or applications in power reactor fluctuations. Furthermore, we have no systematic approach to handle observed time series data in the linear process, since power reactor noise phenomena are complicated. Hence, it is important to study it from the fundamental viewpoint. It is a main aim of the present review paper to describe a unified formalism for reactor system identification and stochastic diagnosis

  9. Tasks related to increase of RA reactor exploitation and experimental potential, 03. Crane for handling the vertical experimental channels of the RA reactor - design project

    International Nuclear Information System (INIS)

    Pavicevic, M.

    1963-07-01

    Within the work related to improvement of experimental potential of the RA reactor, this document describes the design project of the new crane for handling the vertical experimental channels of the RA reactor, engineering drawings of the crane main elements, mechanical part, design project of the electrical part of the crane and cost estimation

  10. Reactor

    International Nuclear Information System (INIS)

    Fujibayashi, Toru.

    1976-01-01

    Object: To provide a boiling water reactor which can enhance a quake resisting strength and flatten power distribution. Structure: At least more than four fuel bundles, in which a plurality of fuel rods are arranged in lattice fashion which upper and lower portions are supported by tie-plates, are bundled and then covered by a square channel box. The control rod is movably arranged within a space formed by adjoining channel boxes. A spacer of trapezoidal section is disposed in the central portion on the side of the channel box over substantially full length in height direction, and a neutron instrumented tube is disposed in the central portion inside the channel box. Thus, where a horizontal load is exerted due to earthquake or the like, the spacers come into contact with each other to support the channel box and prevent it from abnormal vibrations. (Furukawa, Y.)

  11. Current problems arising from the new law relating to franchise duties; Aktuelle Probleme des neuen Konzessionsabgabenrechts

    Energy Technology Data Exchange (ETDEWEB)

    Becker, P.

    1996-12-31

    The contribution examines the advantages and drawbacks of the new ordinance in German law relating to payment of franchise duties. The ordinance may bring about new problems if abused as a means of bringing pressure to bear in negotiations for takeover of existing electric or gas supply systems by local governments. The author analyses the legitimation of such exploitation of the franchise duty and in this context the general legal framework. (orig./CB) [Deutsch] Der Beitrag untersucht Vor- und Nachteile der neuen Verordnung im Konzessionsabgabenrecht, die im Hinblick auf Auseinandersetzungen um die ``Ubernahme von Strom- oder Gasversorgungssystemen durch Gemeinden neue Probleme mit sich bringen koennte, wenn Konzessionsabgaben als Druckmittel eingesetzt werden. Der Autor analysiert die Zulaessigkeit eines derartigen Einsatzes und in diesem Zusammenhang auch die rechtliche Basis der Konzessionsabgaben. (orig./CB)

  12. Power noise spectrum classification in the problem of the IBR-2 reactor

    International Nuclear Information System (INIS)

    Bargel, M.; Kitowski, J.; Pepelyshev, Yu.N.

    1988-01-01

    The classification spectrum results of random fluctuations in the IBR-2 energy pulse are presented. The work is performed for the application of the obtained results to the reactor diagnostics and the study of its noise uncontrolled states. For classification of the spectra the method of pattern recognition based upon the ISODATA heuristic algorithm is used. It is shown that a set of noise uncontrolled reactor states, registered during the reactor operation period at power of 0.4-2 MVt with the first variant of moving reflector (1983-1986) is formed into 4(5) most typical states. Each of the states corresponds to the general conditions of the reactor core cooling and provides the normal work of the moving reflector. However, these states differ in coolant flow, power level and peculiarities of the moving reflector rotation regime. One type of anomal power noise, connected with some disorder in the moving reflctor work, is isolated. This work also presents the possibility of control over the state of moving reflectors according to the change in the amplitude of power oscillations at some frequences. The reactor noise classification results can be used as the data bank for the IBR-2 reactor diagnostic system

  13. Report on safety related occurrences and reactor trips July 1, 1976-December 31, 1976

    International Nuclear Information System (INIS)

    Andermo, L.

    1977-04-01

    This is a systematically arranged report on all reported safety related occurrences and reactor trips in Swedish nuclear power plants in operation during July 1, 1976 to December 31, 1976 inclusive. The facilities involved are Oskarshamn 1 and 2, Ringhals 1 and 2 and Barsebaeck 1. During this period of the 6 months 37 safety related occurrences and 34 reactor trips have been reported to the Nuclear Power Inspectorate. As earlier experiences have shown it is to the greatest extent the conventional components which bring about the safety related occurrences or occurrences leading to outages or power reductions. However, the component errors discovered in the safety related systems have not affected the function of their redundant systems and other diverse systems have not been involved. Therefore the reactor safety has been satisfactory. The fact that even small deviations from prescribed operation results in automatic and safe shut down of the reactor, does not always imply a conflict with operational availability. The number of reactor trips are almost as low as during the last period, which is a drastic reduction compared to earlier time periods. The greatest outages are caused by occurrences without safety significance.(author)

  14. Statistics and Corporate Environmental Management: Relations and Problems

    DEFF Research Database (Denmark)

    Madsen, Henning; Ulhøi, John Parm

    1997-01-01

    Statistical methods have long been used to analyse the macroeconomic consequences of environmentally damaging activities, political actions to control, prevent, or reduce these damages, and environmental problems in the natural environment. Up to now, however, they have had a limited and not very...... in the external environment. The nature and extent of the practical use of quantitative techniques in corporate environmental management systems is discussed on the basis of a number of company surveys in four European countries.......Statistical methods have long been used to analyse the macroeconomic consequences of environmentally damaging activities, political actions to control, prevent, or reduce these damages, and environmental problems in the natural environment. Up to now, however, they have had a limited and not very...... specific use in corporate environmental management systems. This paper will address some of the special problems related to the use of statistical techniques in corporate environmental management systems. One important aspect of this is the interaction of internal decisions and activities with conditions...

  15. Origins and development of the Cauchy problem in general relativity

    International Nuclear Information System (INIS)

    Ringström, Hans

    2015-01-01

    The seminal work of Yvonne Choquet-Bruhat published in 1952 demonstrates that it is possible to formulate Einstein's equations as an initial value problem. The purpose of this article is to describe the background to and impact of this achievement, as well as the result itself. In some respects, the idea of viewing the field equations of general relativity as a system of evolution equations goes back to Einstein himself; in an argument justifying that gravitational waves propagate at the speed of light, Einstein used a special choice of coordinates to derive a system of wave equations for the linear perturbations on a Minkowski background. Over the following decades, Hilbert, de Donder, Lanczos, Darmois and many others worked to put Einstein's ideas on a more solid footing. In fact, the issue of local uniqueness (giving a rigorous justification for the statement that the speed of propagation of the gravitational field is bounded by that of light) was already settled in the 1930s by the work of Stellmacher. However, the first person to demonstrate both local existence and uniqueness in a setting in which the notion of finite speed of propagation makes sense was Yvonne Choquet-Bruhat. In this sense, her work lays the foundation for the formulation of Einstein's equations as an initial value problem. Following a description of the results of Choquet-Bruhat, we discuss the development of three research topics that have their origin in her work. The first one is local existence. One reason for addressing it is that it is at the heart of the original paper. Moreover, it is still an active and important research field, connected to the problem of characterizing the asymptotic behaviour of solutions that blow up in finite time. As a second topic, we turn to the questions of global uniqueness and strong cosmic censorship. These questions are of fundamental importance to anyone interested in justifying that the Cauchy problem makes sense globally. They are

  16. Proposal and analysis of the benchmark problem suite for reactor physics study of LWR next generation fuels

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-10-01

    In order to investigate the calculation accuracy of the nuclear characteristics of LWR next generation fuels, the Research Committee on Reactor Physics organized by JAERI has established the Working Party on Reactor Physics for LWR Next Generation Fuels. The next generation fuels mean the ones aiming for further extended burn-up such as 70 GWd/t over the current design. The Working Party has proposed six benchmark problems, which consists of pin-cell, PWR fuel assembly and BWR fuel assembly geometries loaded with uranium and MOX fuels, respectively. The specifications of the benchmark problem neglect some of the current limitations such as 5 wt% {sup 235}U to achieve the above-mentioned target. Eleven organizations in the Working Party have carried out the analyses of the benchmark problems. As a result, status of accuracy with the current data and method and some problems to be solved in the future were clarified. In this report, details of the benchmark problems, result by each organization, and their comparisons are presented. (author)

  17. Risk of alcohol dependence: prevalence, related problems and socioeconomic factors

    Directory of Open Access Journals (Sweden)

    Juliana Gabrielle Martins-Oliveira

    2016-01-01

    Full Text Available Abstract The present study evaluated the possible alcohol dependence and related problems among adolescents and determined possible associations with socioeconomic factors and gender. A cross-sectional study was conducted with a representative sample of 936 adolescents aged 15 to 19 years enrolled at public and private schools in the city of Belo Horizonte, Brazil. Data related to alcohol consumption and associated problems were collected using the Alcohol Use Disorder Identification Test (AUDIT. The Social Vulnerability Index (SVI, mother's schooling and type of school were used to assess socioeconomic factors. Statistical analysis involved the chi-square test (p < 0.05 and Poisson regression. The prevalence of possible dependence was 16.4%, 52.1% reported concern of a family member regarding the adolescent's alcohol consumption. Female adolescents were less likely to exhibit possible dependence in comparison to males. Participants with living in a low vulnerability area were more likely to consume alcohol in comparison to those living in underprivileged areas. The results of the present study demonstrate that possible dependence was significantly associated with the male gender and low social vulnerability.

  18. Zirconium carbide coating for corium experiments related to water-cooled and sodium-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Plevacova, K. [CEA, DEN, STRI, LMA, Cadarache, 3108 St. Paul lez Durance (France); Journeau, C., E-mail: christophe.journeau@cea.fr [CEA, DEN, STRI, LMA, Cadarache, 3108 St. Paul lez Durance (France); Piluso, P. [CEA, DEN, STRI, LMA, Cadarache, 3108 St. Paul lez Durance (France); Zhdanov, V.; Baklanov, V. [IAE, National Nuclear Centre, Material Structure Investigation Dept., Krasnoarmeiskaya, 10, Kurchatov City (Kazakhstan); Poirier, J. [CEMHTI, 1D, av. de la Recherche Scientifique, 45071 Orleans Cedex 2 (France)

    2011-07-01

    Since the TMI and Chernobyl accidents the risk of nuclear severe accident is intensively studied for existing and future reactors. In case of a core melt-down accident in a nuclear reactor, a complex melt, called corium, forms. To be able to perform experiments with prototypic corium materials at high temperature, a coating which resists to different corium melts related to Generation I and II Water Reactors and Generation IV sodium fast reactor was researched in our experimental platforms both in IAE NNC in Kazakhstan and in CEA in France. Zirconium carbide was selected as protective coating for graphite crucibles used in our induction furnaces: VCG-135 and VITI. The method of coating application, called reactive wetting, was developed. Zirconium carbide revealed to resist well to the (U{sub x}, Zr{sub y})O{sub 2-z} water reactor corium. It has also the advantage not to bring new elements to this chemical system. The coating was then tested with sodium fast reactor corium melts containing steel or absorbers. Undesirable interactions were observed between the coating and these materials, leading to the carburization of the corium ingots. Concerning the resistance of the coating to oxide melts without ZrO{sub 2}, the zirconium carbide coating keeps its role of protective barrier with UO{sub 2}-Al{sub 2}O{sub 3} below 2000 deg. C but does not resist to a UO{sub 2}-Eu{sub 2}O{sub 3} mixture.

  19. Assessment of CFD Codes for Nuclear Reactor Safety Problems - Revision 2

    International Nuclear Information System (INIS)

    Smith, B.L.; Andreani, M.; Bieder, U.; Ducros, F.; Bestion, D.; Graffard, E.; Heitsch, M.; Scheuerer, M.; Henriksson, M.; Hoehne, T.; Houkema, M.; Komen, E.; Mahaffy, J.; Menter, F.; Moretti, F.; Morii, T.; Muehlbauer, P.; Rohde, U.; Krepper, E.; Song, C.H.; Watanabe, T.; Zigh, G.; Boyd, C.F.; Archambeau, F.; Bellet, S.; Munoz-Cobo, J.M.; Simoneau, J.P.

    2015-01-01

    Following recommendations made at an 'Exploratory Meeting of Experts to Define an Action Plan on the Application of Computational Fluid Dynamics (CFD) Codes to Nuclear Reactor Safety (NRS) Problems', held in Aix-en-Provence, France, 15-16 May, 2002, and a follow-up meeting 'Use of Computational Fluid Dynamics (CFD) Codes for Safety Analysis of Reactor Systems including Containment', which took place in Pisa on 11-14 Nov., 2002, a CSNI action plan was drawn up which resulted in the creation of three Writing Groups, with mandates to perform the following tasks: (1) Provide a set of guidelines for the application of CFD to NRS problems; (2) Evaluate the existing CFD assessment bases, and identify gaps that need to be filled; (3) Summarise the extensions needed to CFD codes for application to two-phase NRS problems. Work began early in 2003. In the case of Writing Group 2 (WG2), a preliminary report was submitted to Working Group on the Analysis and Management of Accidents (WGAMA) in September 2004 that scoped the work needed to be carried out to fulfil its mandate, and made recommendations on how to achieve the objective. A similar procedure was followed by the other two groups, and in January 2005 all three groups were reformed to carry out their respective tasks. In the case of WG2, this resulted in the issue of a CSNI report (NEA/CSNI/R(2007)13), issued in January 2008, describing the work undertaken. The writing group met on average twice per year during the period March 2005 to May 2007, and coordinated activities strongly with the sister groups WG1 (Best Practice Guidelines) and WG3 (Multiphase Extensions). The resulting document prepared at the end of this time still represents the core of the present revised version, though updates have been made as new material has become available. After some introductory remarks, Chapter 3 lists twenty-three (23) NRS issues for which it is considered that the application of CFD would bring real benefits

  20. Adaptative numerical methods for transport problems in safety nuclear reactors by the use of perturbations signatures and processes

    International Nuclear Information System (INIS)

    Doriath, J.Y.

    1983-05-01

    The need for increasingly accurate nuclear reactor performance data has led to increasingly sophisticated methods for solving the Boltzmann transport equation. This work has revealed the need for analyzing the functional signatures of the neutron flux using pattern recognition techniques to relate the local and overall phases of reactor calculations according to the desired parameters. This approach makes it possible to develop procedures based on a reference calculations and designed to evaluate the disturbances due to changes in physical media and to media interface modifications [fr

  1. Present status of design, research and development of nuclear fusion reactors and problems

    International Nuclear Information System (INIS)

    1983-04-01

    Seven years have elapsed since the publication of ''Progress of nuclear fusion research and perspective toward the development of power reactors'' by the Atomic Energy Society of Japan in August, 1976. During this period, the research and development of nuclear fusion have changed from plasma physics to reactor technology, being conscious of the realization of fusion reactors. There are the R project in the Institute of Plasma Physics, Nagoya University, and the design and construction of JT-60 in Japan Atomic Energy Research Institute, to put it concretely. Now the research and development taking the economical efficiency into account are adopted. However, the type of fusion reactors is not reduced to tokamak type, accordingly the research and development to meet the diverse possibilities are forwarded. The progress of tokamak reactor research, core plasma design, nuclear design and shielding design, thermal structure design, the design of superconducting magnets, disassembling and repair, safety, economical efficiency, the conceptual design of other types than tokamak and others are reported. (Kako, I.)

  2. Problems in the assessment of inherent safety characteristics of nuclear reactors

    International Nuclear Information System (INIS)

    Garribba, S.F.; Vivante, C.

    1988-01-01

    A number of proposals are being made for an increased RD and D effort on advanced nuclear power reactors that would display outstanding safety performance. A common characteristic of the different reactor concepts would be their limited reliance upon active engineered systems under major accident conditions. However, when submitted to a more close scrutiny reactor concept options may reveal diverging safety behaviors and also development opportunities. In this respect, three issues are explored in this paper. A first question is the meaning of non-active, i.e. inherent and passive safety features. Next, is the ranking of advanced and new reactor concepts from the viewpoint of inherent and passive safety. Multiple correspondence analysis may provide a simple tool, whose use is shown for the case of HTR-500, AP600 and PRISM. Conversely, probabilistic risk assessment would allow quantitative comparisons, although lack of information and data is an obstacle. Finally, is demonstration of safety performances as a step toward market deployment of the new reactor systems

  3. Technical Meeting on Fast Reactors and Related Fuel Cycle Facilities with Improved Economic Characteristics. Working Material

    International Nuclear Information System (INIS)

    2013-01-01

    In recent years, engineering oriented work, rather than basic research and development (R&D), has led to significant progress in improving the economics of innovative fast reactors and associated fuel cycle facilities, while maintaining and even enhancing the safety features of these systems. Optimization of plant size and layout, more compact designs, reduction of the amount of plant materials and the building volumes, higher operating temperatures to attain higher generating efficiencies, improvement of load factor, extended core lifetimes, high fuel burnup, etc. are good examples of achievements to date that have improved the economics of fast neutron systems. The IAEA, through its Technical Working Group on Fast Reactors (TWG-FR) and Technical Working Group on Nuclear Fuel Cycle Options and Spent Fuel Management (TWG-NFCO), devotes many of its initiatives to encouraging technical cooperation and promoting common research and technology development projects among Member States with fast reactor and advanced fuel cycle development programmes, with the general aim of catalysing and accelerating technology advances in these fields. In particular the theme of fast reactor deployment, scenarios and economics has been largely debated during the recent IAEA International Conference on Fast Reactors and Related Fuel Cycles: Safe Technologies and Sustainable Scenarios, held in Paris in March 2013. Several papers presented at this conference discussed the economics of fast reactors from different national and regional perspectives, including business cases, investment scenarios, funding mechanisms and design options that offer significant capital and energy production cost reductions. This Technical Meeting on Fast Reactors and Related Fuel Cycle Facilities with Improved Economic Characteristics addresses Member States’ expressed need for information exchange in the field, with the aim of identifying the main open issues and launching possible initiatives to help and

  4. A Solution to the Cosmological Problem of Relativity Theory

    Science.gov (United States)

    Janzen, Daryl

    After nearly a century of scientific investigation, the standard cosmological theory continues to have many unexplained problems, which invariably amount to one troubling statement: we know of no good reason for the Universe to appear just as it does, which is described extremely well by the flat ΛCDM cosmological model. Therefore, the problem is not that the physical model is at all incompatible with observation, but that, as our empirical results have been increasingly constrained, it has also become increasingly obvious that the Universe does not meet our prior expectations; e.g., the evidence suggests that the Universe began from a singularity of the theory that is used to describe it, and with space expanding thereafter in cosmic time, even though relativity theory is thought to imply that no such objective foliation of the spacetime continuum should reasonably exist. Furthermore, the expanding Universe is well-described as being flat, isotropic, and homogeneous, even though its shape and expansion rate are everywhere supposed to be the products of local energy-content---and the necessary prior uniform distribution, of just the right amount of matter for all three of these conditions to be met, could not have been causally determined to begin with. And finally, the empirically constrained density parameters now indicate that all of the matter that we directly observe should make up only four percent of the total, so that the dominant forms of energy in the Universe should be dark energy in the form of a cosmological constant, Λ, and cold dark matter (CDM). The most common ways of attacking these problems have been: to apply modifications to the basic physical model, e.g. as in the inflation and quintessence theories which strive to resolve the horizon, flatness, and cosmological constant problems; to use particle physics techniques in order to formulate the description of dark matter candidates that might fit with observations; and, in the case of the Big

  5. The reactor core configuration and important systems related to physics tests of Daya Bay NPP

    International Nuclear Information System (INIS)

    Tao Shaoping

    1995-06-01

    A brief introduction to reactor core configuration and important systems related to physics tests of Daya Bay NPP is given. These systems involve the reactor core system (COR), the full length rod control system (RGL), the in-core instrumentation system (RIC), the out-of-core nuclear instrumentation system (RPN), and the LOCA surveillance system (LSS), the centralized data processing system (KIT) and the test data acquisition system (KDO). In addition, that the adjustment and evaluation of boron concentration related to other systems, for example the reactor coolant system (RCP), the chemical and volume control system (RCV), the reactor boron and water makeup system (REA), the nuclear sampling system (REN) and the reactor control system (RRC), etc. is also described. Analysis of these systems helps not only to familiarize their functions and acquires a deepen understanding for the principle procedure, points for attention and technical key of the core physics tests, but also to further analyze the test results. (3 refs., 11 figs., 1 tab.)

  6. Alpha decay and various problems related to it

    International Nuclear Information System (INIS)

    Katori, Kenji

    1992-01-01

    On the proton-excessive nucleus side of lanthanide and actinide, alpha decay is the main decay mode. In lanthanide region, alpha decay has been measured to the drip line for most even-even nuclei. In the measurement of alpha decay, emitted energy and life are measured, but the measurement of converted alpha width remains in the limited range. In order to obtain the converted alpha width of high accuracy, the nucleus formation in larger quantity on the drip line and the simultaneous measurement with a multiple detector system including gamma ray and beta ray are required. In this paper, three topics related to alpha cluster and alpha decay and the problems that confront at present are discussed. The continuation to exist of alpha cluster structure to heavy nuclei, the analysis of lanthanide nucleus region by the alpha giant resonance model, and the new data on the alpha ray decaying from the mass of 175, 176 and 177 are reported. In lanthanide nucleus region, remarkable interference was not observed between beta-2 and beta-3 modes in the converted alpha width measured between the ground states. The present problems in alpha decay are enumerated. (K.I.)

  7. Thermal and flow design of helium-cooled reactors

    International Nuclear Information System (INIS)

    Melese, G.; Katz, R.

    1984-01-01

    This book continues the American Nuclear Society's series of monographs on nuclear science and technology. Chapters of the book include information on the first-generation gas-cooled reactors; HTGR reactor developments; reactor core heat transfer; mechanical problems related to the primary coolant circuit; HTGR design bases; core thermal design; gas turbines; process heat HTGR reactors; GCFR reactor thermal hydraulics; and gas cooling of fusion reactors

  8. The principle of relativity and the problem of knowledge

    International Nuclear Information System (INIS)

    Suarez Antola, R.

    2011-01-01

    This book can be considered as an introduction to some issues on the border between philosophy and science. It is intended for an audience interested in the problems that arise in scientific knowledge about the so-called post-modern era, and willing to study in some detail and depth the physical and mathematical foundations of the theory of relativity, and some of applications in astrophysics and cosmology. It assumes familiarity with the epistemology and other branches of philosophy. The philosophical content, including epistemological, are introduced as needed, starting with the first chapter is intended entirely to them, culminating in the fourteenth chapter, which discusses the structure of the theory of relativity, the theory general physics and cosmology from that point of view. In his chapters describes: the development of ideas in the Newtonian mechanics of particles and the classical theory of fields, including electromagnetism, the crisis in the foundations of nineteenth-century physics, the foundations, limitations and some applications of restricted theory, knowledge of mathematics, calculus of variations, foundations of general relativity theory, applications Schwartzschild solution, applications in astronomy and cosmology, relativistic physics issues and finally, aspects of scientific research work from the point of psychological and sociological

  9. Problems Related to the Translation of Political Texts

    Directory of Open Access Journals (Sweden)

    Sárosi-Márdirosz Krisztina

    2015-03-01

    Full Text Available This study deals with the problems related to the translation of political texts in the theoretical framework elaborated by the researchers working in the field of translation studies and reflects on the terminological peculiarities of the special language used for this text type. Consideration of the theoretical framework is followed by the analysis of a specific text spoken then written in English and translated into Hungarian and Romanian. The conclusions are intended to highlight the fact that there are no recipes for translating a political speech, because translation is not only a technical process that uses translation procedures and applies transfer operations, but also a matter of understanding cultural, historical and political situations and their significance.

  10. The benefits and problems of base seismic isolation for LMFBR reactor plants

    International Nuclear Information System (INIS)

    Seidensticker, R.W.

    1988-01-01

    The use of seismic isolation as an approach to aseismic design has gained increasing interest as a viable and efficient engineering solution to earthquake ground motion both within and outside of the nuclear field. Seismic isolation design is fundamentally different from conventional design practice. In the conventional approach, seismic loads are resisted by making the structures, equipment, piping, and associated supports strong enough to resist seismic loads and to provide high levels of ductility. The use of seismic isolation approaches the problem by decoupling the structure (and its contents) from the seismic input resulting from ground shaking. Because LMFBR systems operate at virtually atmospheric pressure, vessels, piping, and associated components tend to be quite thin-walled. The problem is that these thin-walled items have little inherent resistance to earthquake effects and are vulnerable to seismic load effects. As a result, earthquake loads have an even greater influence on LMR designs than they already are in LWR plants. The potential benefits of seismic isolation for an LMR plant are considerable, including minimization of high-cost commodities such as stainless steel, large reductions in internal equipment loads, increased margins of safety for beyond-design-basis loads, and enhancement of plant standardization design. There are, of course, a number of issues and concerns in the use of seismic isolation for a nuclear power plant. These issues cover a number of items such as the lack of experience in actual earthquakes, effects of long-period ground motion, effect of vertical loads, traveling waves, and other related concerns. This paper presents an evaluation of the benefits and problems in the use of seismic isolation in LMR plants. 12 refs, 7 figs

  11. The collapsing of multigroup cross sections in optimization problems solved by means of the Pontryagin maximum principle in nuclear reactor dynamics

    International Nuclear Information System (INIS)

    Anton, V.

    1979-12-01

    The collapsing formulae for the optimization problems solved by means of the Pontryagin maximum principle in nuclear reactor dynamics are presented. A comparison with the corresponding formulae of the static case is given too. (author)

  12. Problems in producing nuclear reactor for medical isotopes and the Global Crisis of molybdenum supply

    International Nuclear Information System (INIS)

    Zubiarrain, A.

    2011-01-01

    Nuclear medicine uses drugs that incorporate a radioactive isotope radiopharmaceuticals. Every year are performed, worldwide, 35 million nuclear medicine procedures, of which 80% are done with radiopharmaceuticals containing the isotope, molybdenum-99, produced in nuclear reactors. In recent years, there have been several supply crisis of molybdenum-99, which have hampered diagnostic procedure with technitium-99m. (Author)

  13. Adaptation of eddy current methods to the multiple problems of reactor testing

    International Nuclear Information System (INIS)

    Stumm, W.

    1975-01-01

    In reactor testing, the eddy current method is mainly used for the testing of surface regions inside the pressure vessel, on welds and joints, and for the testing of thin-walled pipes, e.g. the heat exchanger pipes. (RW/AK) [de

  14. Technical problems in case of utilizing uranium of medium enrichment for a research reactor

    International Nuclear Information System (INIS)

    Kanda, Keiji; Shibata, Shun-ichi

    1979-01-01

    Usually, highly enriched uranium of 90 - 93% is used for research reactors, but the US government proposed the strong policy to use low enriched uranium of the uranium of medium enrichment in unavoidable case from the viewpoint of the resistance to nuclear proliferation in November, 1977. This policy is naturally applied to Japan also. The export of highly enriched uranium will be permitted only when the President approves it after the technical and economical evaluations by the government. The Kyoto University high flux reactor has the features which are not seen in other research reactors, such as medical irradiation, and it is hard to attain the objectives of researches unless HEU is used. The application for the export of HEU was accepted in February, 1978. The nuclear characteristics of the KUHFR when medium or low enriched uranium is used, the criticality experiment in the KUCA using the uranium of medium enrichment, and the burning test on the uranium fuel plates of medium enrichment are described. The research project to lower the degree of enrichment in the fuel for research and test reactors is expected to be continued down to less than 20%. The MEU of 45% enrichment will be actually used in 1983. (Kako, I.)

  15. Problems of evaluation of nuclear reactor active zone tubes during pre-irradiation tests

    International Nuclear Information System (INIS)

    Lezinskaya, E.Ya.; Buryak, T.N.

    2004-01-01

    An analysis of standard methods of graine size estimation of basic indexes of austenitic steel and alloys of active area of atomic reactors. It is shown insolvency of standard methods of grain size estimation in the real wares. The suggested method of computer simulation of structures of pipes-shells raped for working aut of modes of heat treatment

  16. RA Reactor

    International Nuclear Information System (INIS)

    1978-02-01

    In addition to basic characteristics of the RA reactor, organizational scheme and financial incentives, this document covers describes the state of the reactor components after 18 years of operation, problems concerned with obtaining the licence for operation with 80% fuel, problems of spent fuel storage in the storage pool of the reactor building and the need for renewal of reactor equipment, first of all instrumentation [sr

  17. Research on neutron radiography in Research Reactor Institute, Kyoto University and activities related to it

    International Nuclear Information System (INIS)

    Fujine, Shigenori; Yoneda, Kenji

    1994-01-01

    The research on neutron radiography in Research Reactor Institute, Kyoto University was begun in 1974 using the E-2 experimental hole which was designed for neutron irradiation. It was reconstructed for the excellent performance as neutron radiography facility by fixing aluminum plugs, a collimator and so on. The research activities thereafter are briefly described. In 1989, the cold neutron facility was installed in the graphite thermal neutron facility, and the experiment on cold neutron radiography became feasible. The reactor in Kyoto University is of the thermal output of 5 MW, and is put to the joint utilization by universities and research institutes in whole Japan. The experimental items carried out so far are enumerated. At present, the main subjects of research are the development of the standard for establishing image evaluation method, the analysis of gas-liquid two-phase flow, the construction of the data base for the literatures and images of neutron radiography, the application of cold neutron radiography, the development of the imaging method using fast neutrons and so on. The thermal neutron radiography and the cold neutron radiography facilities of Kyoto University research reactor are described. The research and activities at Kyoto University research reactor and the investigation of problems are reported. (K.I.) 56 refs

  18. Intercultural communication problems relating to translation from English into Sesotho

    Directory of Open Access Journals (Sweden)

    Anastacia Sara Motsei

    2013-12-01

    Full Text Available In this article, certain translative communication problems associated with the linguistic and stylistic differences between English and Sesotho are identified and discussed. With a view to help improve translation between the two languages where inaccurate and stilted communication frequently occurs, issues of equivalence, fidelity/faithfulness and the purpose of translation are delved into. It is furthermore argued that in South African multilingual contexts, like legal courts, criminal cases/hearings and hospitals clinics and similar health establishments, inaccurate translation and/or misinterpreting can lead to serious miscarriages of justice and poor service delivery. The reasons for such unfortunate eventualities sometimes relate to the translator-interpreter’s poor understanding of the cultural factors behind the English or Sesotho message. As such, emphasis is lain on the need for a translator-interpreter’s cultural understanding of the source language/text (SL/T and target language/text (TL/T to deliver an accurate version (in the target language or text – TL/T of the original message. It is furthermore shown that one cause of social and legal injustice is closely related to the translator- interpreter’s insufficient knowledge of both the English and Sesotho culture as it exists in grammatical forms, idiomatic structures, collocation patterns and stylistic patterns of the SL/T and the TL/T.

  19. Relative hazard potential: the basis for definition of safety criteria for fast reactors

    International Nuclear Information System (INIS)

    Cave, L.; Ilberg, D.

    1977-02-01

    One of the main safety criteria to be met for larger thermal reactors is that the probability of exceeding the dose limits imposed by 10 CRF 100 should not be greater than 10 per reactor year. The potential hazard presented by a fast reactor could be substantially greater than that due to an LWR. The potential for harm of a reactor system may be judged by the effects which would arise from a severe accident. Several different types of effects may be considered: number of latent fatal cancers; number of deaths due to acute effects; number of thyroid tumors or nodules; extent of property damage; and genetic effects. Analytical methods for comparison are employed in this paper. A second important parameter reviewed in this report is the radio-toxicity attributed to the various isotopes. It was found that the worst conceivable accident to a 1000 MW(e) fast reactor would lead to effects on health greater by an order of magnitude than the worst accident usually considered for an LWR. Therefore, some reconsideration of the need for additional safety criteria for LMFBRs, as a guide to designers in relation to the control of the effects of very severe accidents, is desirable

  20. Pediatrician-parent-child communication: problem-related or not?

    NARCIS (Netherlands)

    Dulmen, S. van

    2004-01-01

    Pediatricians are generally confronted with a variety of health problems. Each of these problems may benefit from another pattern of healthcare communication. It is unknown whether the communication process during pediatric visits actually differs by the nature of the child's problem. This study

  1. Corrosion of reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1963-01-15

    Much operational experience and many experimental results have accumulated in recent years regarding corrosion of reactor materials, particularly since the 1958 Geneva Conference on the Peaceful Uses of Atomic Energy, where these problems were also discussed. It was, felt that a survey and critical appraisal of the results obtained during this period had become necessary and, in response to this need, IAEA organized a Conference on the Corrosion of Reactor Materials at Salzburg, Austria (4-9 June 1962). It covered many of the theoretical, experimental and engineering problems relating to the corrosion phenomena which occur in nuclear reactors as well as in the adjacent circuits

  2. An holistic approach to the problem of reactor ageing. [Pressure vessel embrittlement

    Energy Technology Data Exchange (ETDEWEB)

    Phythian, W.; McElroy, R.; Druce, S.; Kovan, D. (AEA Reactor Services, Harwell (United Kingdom))

    1992-12-01

    Understanding the process of ageing in reactors is essential to extending their lives beyond original design. To present a sound case -particularly regarding the level of embrittlement in reactor vessels due to radiation damage - an integrated approach using advanced assessment tools is needed. The techniques developed for the purpose involve, on the microscopic level, advanced neutron dosimetry and high resolution measurement techniques (eg advanced electron beam techniques and small angle neutron scattering) with which an analysis can be done of the radiation damage and the microstructural state of the steel test procedures (tensile, fracture toughness and Charpy impact) on standard and sub-sized specimens, the extent of radiation degradation can be characterised. finally, it is possible to predict how the degradation will evolve using physically-based models of embrittlement. (Author).

  3. Materials science problems of blankets in Russian concept of fusion reactor

    International Nuclear Information System (INIS)

    Solonin, M.I.

    1998-01-01

    Structural materials, beryllium and tritium breeding materials proposed for blanket of Russian reactor DEMO and Test Modules for ITER are discussed. Main requirements for the materials are concerned with basis current designs of blankets and modules and possibility meet of ones for presence and developed alloys and materials discussed considered. Main properties and results of test of ferrite-martensite and vanadium alloys for DEMO and Test Modules are cited. Beryllium compositions used as component of first wall and neutron multiplier are discussed. Liquid lithium and ceramic (lithium orthosilicate) are treated as tritium breeding materials. Russian development of reactor experimental unit for tritium breeding zone using beryllium, lithium ceramic and ferrite-martensite alloys for structural materials is presented. (orig.)

  4. A systematic approach to the radiation damage problem in reactor materials

    International Nuclear Information System (INIS)

    Bullough, R.; Eyre, B.L.; Kulcinski, G.L.

    1976-09-01

    To assess the suitability of a material for use as a core component in a fast reactor or for the first wall in a fusion reactor, it is necessary to know the irradiation damage behaviour of the material outside the usual materials testing data domain. In the present paper a strategy is proposed based on a closely co-ordinated programme of experimental and theoretical research. The aim of this strategy is the systematic construction of a physically based model of the evolving damage structures. This would then allow both the necessary extrapolations of the data to the desired conditions to be achieved in a reliable fashion and provide a rational basis for the development of low swelling alloys for the two nuclear systems. (author)

  5. On the problem of in-core fuel management in power reactors

    International Nuclear Information System (INIS)

    Marinkovic, N.; Matausek, M.V.

    1985-01-01

    Within the scope of in-core fuel management including refuelling schedule and reactivity control it is indispensable to define nuclear fuel worth, optimal depletion of the spent fuel assemblies as well as isotopic composition of the spent fuel. This paper shows the computed values of the mentioned parameters in case of different reactor types, PWR, WWER, HWR and BWR of 1000 MWe as well as the intensity of radiation of the spent fuel 3 and 1 years after fission.(author)

  6. Problems of two-phase flows in water cooled and moderated reactors

    International Nuclear Information System (INIS)

    Syu, Yu.

    1984-01-01

    Heat exchange in two-phase flows of coolant in loss of coolant accidents in PWR and BWR reactors has been investigated. Three main stages of accident history are considered: blowdown, reflooding using emergency core cooling system and rewetting. Factors, determining the rate of coolant leakage and the rate of temperature increase in fuel cladding during blowdown, processes of vapour during reflooding and liquid priming by vapour during rewetting, are discussed

  7. Hot steam header of a high temperature reactor as a benchmark problem

    International Nuclear Information System (INIS)

    Demierre, J.

    1990-01-01

    The International Atomic Energy Agency (IAEA) initiated a Coordinated Research Programme (CRP) on ''Design Codes for Gas-Cooled Reactor Components''. The specialists proposed to start with a benchmark design of a hot steam header in order to get a better understanding of the methods in the participating countries. The contribution of Switzerland carried out by Sulzer. The following report summarized the detailed calculations of dimensioning procedure and analysis. (author). 5 refs, 2 figs, 2 tabs

  8. Goals and everyday problem solving: examining the link between age-related goals and problem-solving strategy use.

    Science.gov (United States)

    Hoppmann, Christiane A; Coats, Abby Heckman; Blanchard-Fields, Fredda

    2008-07-01

    Qualitative interviews on family and financial problems from 332 adolescents, young, middle-aged, and older adults, demonstrated that developmentally relevant goals predicted problem-solving strategy use over and above problem domain. Four focal goals concerned autonomy, generativity, maintaining good relationships with others, and changing another person. We examined both self- and other-focused problem-solving strategies. Autonomy goals were associated with self-focused instrumental problem solving and generative goals were related to other-focused instrumental problem solving in family and financial problems. Goals of changing another person were related to other-focused instrumental problem solving in the family domain only. The match between goals and strategies, an indicator of problem-solving adaptiveness, showed that young individuals displayed the greatest match between autonomy goals and self-focused problem solving, whereas older adults showed a greater match between generative goals and other-focused problem solving. Findings speak to the importance of considering goals in investigations of age-related differences in everyday problem solving.

  9. Application of hexagonal element scheme in finite element method to three-dimensional diffusion problem of fast reactors

    International Nuclear Information System (INIS)

    Ishiguro, Misako; Higuchi, Kenji

    1983-01-01

    The finite element method is applied in Galerkin-type approximation to three-dimensional neutron diffusion equations of fast reactors. A hexagonal element scheme is adopted for treating the hexagonal lattice which is typical for fast reactors. The validity of the scheme is verified by applying the scheme as well as alternative schemes to the neutron diffusion calculation of a gas-cooled fast reactor of actual scale. The computed results are compared with corresponding values obtained using the currently applied triangular-element and also with conventional finite difference schemes. The hexagonal finite element scheme is found to yield a reasonable solution to the problem taken up here, with some merit in terms of saving in computing time, but the resulting multiplication factor differs by 1% and the flux by 9% compared with the triangular mesh finite difference scheme. The finite element method, even in triangular element scheme, would appear to incur error in inadmissible amount and which could not be easily eliminated by refining the nodes. (author)

  10. Problems Related to the Abolition of Divided Real Estate Ownership

    Directory of Open Access Journals (Sweden)

    Dinsberga Jolanta

    2016-12-01

    Full Text Available Legal relationship between apartment owners in residential buildings and the land owners, that is, divided real estate ownership, was created in the Republic of Latvia in 1990, within the framework of the Land Reform, restoring property rights of the former owners or their heirs or privatising apartments in multi-apartment residential buildings. The existence of such legal relationship created different lease problems and restrictions on the property rights to the owners of both the building and the land. To abolish the legal relationship related to divided real estate ownership, the Ministry of Justice of the Republic of Latvia has developed a draft law Regarding the Abolition of Mandatory Divided Real Estate Ownership in Multi-Apartment Buildings (hereinafter referred to as Draft Law. Unfortunately, in the opinion of authors of this article, there are serious shortcomings to the Draft Law which must be corrected. The aim of the research is to identify the problematic issues by selecting and analysing the legislation on the abolition of the divided real estate ownership, which is related to the calculation of redemption price, payment method and consequences of non-payment, which are not regulated by the new Draft Law. The article reflects research on the determination and calculation of redemption price reglamented by the Draft Law and also analyses the Law of December 8, 1938, On the Abolition of Divided Real Estate Ownership and its practical implementation, which may significantly influence the redemption price and the method of its calculation; however, the mentioned law has been disregarded in developing the Draft Law. Thus the research has both theoretical and practical significance. For the research purposes general research methods, such as historical, analytical, inductive, deductive, logical-constructive and descriptive methods, are used. For the interpretation of legislation norms, grammatical, systemic, teleological and historical

  11. [Stomatological problems related to pregnancy. A statistical study].

    Science.gov (United States)

    Masoni, S; Panattoni, E; Rolla, P; Rossi, M; Giuca, M R; Gabriele, M

    1991-12-01

    Pregnancy is related to particular dental issues, such as the increased incidence of diseases( gingivitis, caries, epulis), the fluoride supplementation, and the limits of diagnostics and therapy. Moreover, the mysterious halo surrounding pregnancy often makes the dentist uneasy. In order to objectively evaluate the implications of pregnancy in dentistry, we distributed a form to 100 pregnant women. The results of the form showed that 53 of them had gingival bleeding, 22 had toothache, 19 had caries but that just 12 of them had gone to the dentist because of dental troubles while 54 had not gone at all. Among the pluri-gravidae, all the women with dental diseases in their previous pregnancies had them again in their current pregnancy but nonetheless only some had undergone a dental check-up. The dentists did not show any uneasiness, as they performed tooth extractions in 5 women, endodontics in 2 women and fillings in 11 women. Just 4 out of 100 women had taken a fluoride supplementation. We deem advisable a stronger collaboration between physician, gynecologist and dentist in order to resolve specialist problems and to make pregnant women more aware of the need for dental follow-ups and fluoride supplementations.

  12. Are maternal fertility problems related to childhood leukaemia

    International Nuclear Information System (INIS)

    Steensel-Moll, H.A. van; Valkenburg, H.A.; Vandenbroucke, J.P.; Zanen, G.E. van

    1985-01-01

    A study was conducted in the Netherlands, from a nationwide register of childhood leukaemia (1973-1980). Controls were matched with cases for year of birth, sex and place of residence. Information about exposures of the mother to potential risk factors in the year before and during pregnancy was collected via mailed questionnaires. Analyses concerned data on 519 patients with acute lymphocytic leukaemia and 507 controls. An association between maternal subfertility and childhood leukaemia might be suggested by several findings. A history of two or more miscarriages (OR 1.6; 95% Cl 1.0-2.7) and fertility problems (OR 6.0; 95% Cl 0.9-38.2) were more frequently reported among mothers of cases. Use of oral contraceptives (OC) was significantly higher (OR 1.3; 95% Cl 1.0-1.8) and the duration between discontinuation of OC and the relevant pregnancy was significantly longer. The OR for threatened abortion during the relevant pregnancy was 1.6 (95% Cl 1.0-2.6) and the related use of 'drugs to maintain pregnancy' was 1.9; 95% Cl 1.0-3.5. Among known risk factors, an increased OR for diagnostic irradiation was confirmed (OR 2.2; 95% Cl 1.2-3.8). No association between childhood leukaemia and prenatal viral infections, smoking and alcohol was found. (author)

  13. Energy use and related risk management problems in CEE countries

    International Nuclear Information System (INIS)

    Ney, R.; Michna, J.; Ekmanis, J.; Zeltins, N.; Zebergs, V.

    2008-01-01

    Nowadays, the efficiency of energy use in the Central and East-European (CEE) countries is insufficient, being much lower than in the 'Old Europe'. The problem becomes increasingly pressing due to non-stop increasing prices of energy carriers (especially of crude oil). The authors trace the development of research activities in this sphere, classifying the revealed changes in parameters of energy consumption processes in particular time intervals into deterministic, probabilistic, and fuzzy. The paper presents a thorough analysis of decision-making in the energy management at its different levels normative, strategic, and operative. Particular attention is given to the management under uncertainty conditions - i.e. to the risk management. The most wanted research directions in this area proposed by the energy and environment policy (EEP) Center specially created for CEE countries concern management under risk connected with innovations, international activities, loss of reputation, etc.. The authors consider in detail the risk management with insufficient knowledge (non-knowledge) and under chaos. Much consideration is given to the scenario management and the game theory principles as related to the sphere of energy use. (Authors)

  14. Water Related Health Problems in Central Asia—A Review

    Directory of Open Access Journals (Sweden)

    Zakir Bekturganov

    2016-05-01

    Full Text Available The present paper provides an extensive literature review on water related health issues in Central Asia. Even though the per capita amount of available freshwater is substantial in all Central Asian states the uneven distribution in time and space creates problems for water availability. Due to this, the Central Asian economies are developing under increasing water deficiency. The degradation of water supply systems and sewage treatment plants is often severe leading to potentially high water loss rates and inadequate accessibility to safe water supply. In this context, rural areas are the most affected. Low tariffs in combination with absent metering and low collection rates for water fees mean that operation and maintenance costs for basic services of water supply and sanitation are not covered. Unsafe water supply contains both microbiological and non-microbiological contaminants. Helminthiasis and intestinal protozoa infections are of considerable public health importance in Central Asia. Agricultural and industrial pollution is especially affecting downstream areas of Amu Darya and Syr Darya rivers. In large areas copper, zinc, and chromium concentrations in water exceed maximum permissible concentration. Thus, there is an urgent need to strengthen the environmental monitoring system. Small-scale water supply and sanitation systems need to be developed in line with more efficient public spending on these.

  15. Some problems relating to application of safeguards in the future

    International Nuclear Information System (INIS)

    Tolchenkov, D.L.

    1983-01-01

    By the end of this century there will have been a considerable increase in the amount of nuclear material and the number of facilities subject to IAEA safeguards. The IAEA will therefore be faced with problems due to the increased volume of safeguards activity, the application of safeguards to new types of facility and to large facilities, the optimization of the existing IAEA safeguards system and so on. The authors analyse the potential growth in the IAEA's safeguards activities up to the year 2000 and consider how to optimize methods for the application of safeguards, taking into account a number of factors relating to a State's nuclear activity, the application of full-scope IAEA safeguards etc. On the basis of a hypothetical model of the nuclear fuel cycle that allows for the factors considered as part of the International Nuclear Fuel Cycle Evaluation (INFCE), the authors assess the possible risk of diversion as a function of a full-scope safeguards effort. They also examine possible conceptual approaches to safeguarding large-scale facilities such as fuel reprocessing and uranium enrichment plants. (author)

  16. Explicitly solvable complex Chebyshev approximation problems related to sine polynomials

    Science.gov (United States)

    Freund, Roland

    1989-01-01

    Explicitly solvable real Chebyshev approximation problems on the unit interval are typically characterized by simple error curves. A similar principle is presented for complex approximation problems with error curves induced by sine polynomials. As an application, some new explicit formulae for complex best approximations are derived.

  17. Comparison of problems and experience of core operation with distorted fuel element assemblies in VVER-1000 and PWR reactors

    International Nuclear Information System (INIS)

    Afanas'ev, A.

    1999-01-01

    The main reactors leading to distortion of fuel element assemblies during reactor operation were studied. A series of actions which compensate this effect was proposed. Criteria of operation limitation in VVER-1000 and PWR reactors are described

  18. Community mobilization and the framing of alcohol-related problems.

    Science.gov (United States)

    Herd, Denise

    2010-03-01

    The goal of this study was to describe how activists engaged in campaigns to change alcohol policies in inner city areas framed alcohol problems, and whether or not their frameworks reflected major models used in the field, such as the alcoholism as a disease model, an alcohol problems perspective, or a public health approach to alcohol problems. The findings showed that activists' models shared some aspects with dominant approaches which tend to focus on individuals and to a lesser extent on regulating alcohol marketing and sales. However, activists' models differed in significant ways by focusing on community level problems with alcohol; on problems with social norms regarding alcohol use; and on the relationship of alcohol use to illicit drugs.

  19. Community Mobilization and the Framing of Alcohol-Related Problems

    Directory of Open Access Journals (Sweden)

    Denise Herd

    2010-03-01

    Full Text Available The goal of this study was to describe how activists engaged in campaigns to change alcohol policies in inner city areas framed alcohol problems, and whether or not their frameworks reflected major models used in the field, such as the alcoholism as a disease model, an alcohol problems perspective, or a public health approach to alcohol problems. The findings showed that activists’ models shared some aspects with dominant approaches which tend to focus on individuals and to a lesser extent on regulating alcohol marketing and sales. However, activists’ models differed in significant ways by focusing on community level problems with alcohol; on problems with social norms regarding alcohol use; and on the relationship of alcohol use to illicit drugs.

  20. Application of Decomposition Methodology to Solve Integrated Process Design and Controller Design Problems for Reactor-Separator-Recycle System

    DEFF Research Database (Denmark)

    Abd.Hamid, Mohd-Kamaruddin; Sin, Gürkan; Gani, Rafiqul

    2010-01-01

    This paper presents the integrated process design and controller design (IPDC) for a reactor-separator-recycle (RSR) system and evaluates a decomposition methodology to solve the IPDC problem. Accordingly, the IPDC problem is solved by decomposing it into four hierarchical stages: (i) pre...... the design of a RSR system involving consecutive reactions, A B -> C and shown to provide effective solutions that satisfy design, control and cost criteria. The advantage of the proposed methodology is that it is systematic, makes use of thermodynamic-process knowledge and provides valuable insights......-analysis, (ii) design analysis, (iii) controller design analysis, and (iv) final selection and verification. The methodology makes use of thermodynamic-process insights and the reverse design approach to arrive at the final process-controller design decisions. The developed methodology is illustrated through...

  1. Some problems of software development for the plant-level automated control system of NPPs with the RBMK reactors

    International Nuclear Information System (INIS)

    Gorbunov, V.P.; Egorov, A.K.; Isaev, N.V.; Saprykin, E.M.

    1987-01-01

    Problems on development and operation of automated control system (ACS) software of NPPs with the RBMK reactors are discussed. The ES computer with large on-line storage (not less than 1 Mbite) and fast response (not less than 300.000 of operations per a second) should enter the ACS composition. Several program complexes are used in the NPP ACS. The programs collected into the EhNERGIYa library are used to provide central control system operation. The information-retrival system called the Fuel file is used to automate NPP fuel motion account, as well as to estimate efficiency of fuel application, to carry out calculations of a fuel component of electric and heat energy production cost. The automated information system for unit operation efficiency analysis, which solves both plant and unit-level problems, including engineering and economical factors and complexing of operation parameter bank, is under trial operation

  2. Substantiation of vibration strength of nuclear reactor and steam generator internals. Main problems

    International Nuclear Information System (INIS)

    Fyodorov, V.G.; Sinyavasky, V.F.

    1977-01-01

    The report details the scope and priority of studies necessary for substantiation of vibration strength of steam generator tube bundles and reactor fuel assemblies, and design modifications helping to reduce flow-induced vibration of the internals specified. Steam generator tube bundles are studied on the basis of a standard establishing vibration requirements at various stages of design, manufacture and operation of a steam generator at a nuclear power station. The main vibration characteristics of tubes obtained through model and full-scale tests are compared with calculation results. Results are provided concerning test-stand vibration tests of fuel elements and fuel assemblies. (author)

  3. Neutron multiplication and shielding problems in pressurized water reactor spent fuel shipping casks

    International Nuclear Information System (INIS)

    Devillers, C.; Blum, P.

    1977-01-01

    To evaluate the degree of accuracy of computational methods used in the shield design of spent fuel shipping casks, comparisons have been made between biological dose-rate calculations and measurements at the surface of a cask carrying three pressurized water reactor fuel assemblies. Neutron dose-rate measurements made with the fuel-carrying region successively wet and dry are also used to derive an experimental value of the k/sub eff/ of the wet fuel assemblies. Results obtained by this method are shown to be consistent with criticality calculations, taking into account fuel depletion

  4. Problems in experimental and mathematical investigations of the accidental thermalhydraulic processes in RBMK nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Nigmatulin, B.I.; Tikhonenko, L.K. [Engineering Centre (EREC) for Nuclear Plants Safety, Electrogorsk (Russian Federation); Blinkov, V.N. [Aviation Institute, Kharkov (Ukraine)] [and others

    1995-09-01

    In this paper the thermalhydraulic scheme and peculiarities of the boiling water graphite-moderated channel-type reactor RBMK are presented and discussed shortly. The essential for RBMK transient regimes, accidental situations and accompanying thermalhydraulic phenomena and processes are formulated. These data are presented in the form of cross reference matrix (version 1) for system computer codes verification. The paper includes qualitative analysis of the computer codes and integral facilities which have been used or can be used for RBMK transients and accidents investigations. The stability margins for RBMK-1000 and RBMK-1500 are shown.

  5. Problems in tritium handling in fusion reactors studies at CEA within the european effort

    International Nuclear Information System (INIS)

    Roth, E.; Hircq, B.; Fidelle, J.P.

    1988-01-01

    Technological aspects of tritium handling linked with the operation of a fusion reactor are reviewed. Tritium storage is discussed from the point of view of the volumme of a single unit and of the nature of the metal bed. Purification of tritium and recovery from tritiated compounds is studied, including conversion from water to the gaseous form. Interaction of tritium and structural materials is developed from the point of view of corrosion, embrittlement, permeation. A flowsheet displaying a conception of a reference tritium circuit is proposed, and consideration is given to specifications of large components, namely pumps and gatevalves for tritium circuits

  6. Safety assessments relating to the use of new fuels in research reactors: application to the case of FRM 2 reactor fuel

    International Nuclear Information System (INIS)

    Abou Yehia, H.; Bars, G.; Tran Dai

    2001-01-01

    After giving a brief reminder of the procedure applied in France for the licensing of the use of a new fuel type or design in a research reactor, we outline the main safety aspects associated with such a modification. Finally, by way of an example, we focus on the safety assessment relating to the IRIS irradiation device used in SILOE reactor, in particular for the qualification of the fuel dedicated to FRM II reactor of the Technical University of Munich. This qualification was carried out on a U 3 Si 2 fuel plate enriched to about 90 % in weight of 235 U and containing 1.5 g of uranium per cm 3 . The evaluation performed by the IPSN for GRS did not call into question the choice of U 3 Si 2 fuel plates for the FRM-II reactor. (authors)

  7. Importance sampling implemented in the code PRIZMA for deep penetration and detection problems in reactor physics

    International Nuclear Information System (INIS)

    Kandiev, Y.Z.; Zatsepin, O.V.

    2013-01-01

    At RFNC-VNIITF, the PRIZMA code which has been developed for more than 30 years, is used to model radiation transport by the Monte Carlo method. The code implements individual and coupled tracking of neutrons, photons, electrons, positrons and ions in one dimensional (1D), 2D or 3D geometry. Attendance estimators are used for tallying, i.e., the estimators whose scores are only nonzero from particles which cross a region or surface of interest. Importance sampling is used to make deep penetration and detection calculations more effective. However, its application to reactor analysis appeared peculiar and required further development. The paper reviews methods used for deep penetration and detection calculations by PRIZMA. It describes in what these calculations differ when applied to reactor analysis and how we compute approximated importance functions and parameters for biased distributions. Methods to control the statistical weight of particles are also discussed. A number of test and applied calculations which were done for the purpose of verification are provided. They are shown to agree either with asymptotic solutions if exist, or with results of analog calculations or predictions by other codes. The applied calculations include the estimation of ex-core detector response from neutron sources arranged in the core, and the estimation of in-core detector response. (authors)

  8. Solenoid pick-up problem in the CREN-K Triga Mark 2 reactor

    International Nuclear Information System (INIS)

    Malu wa Kalenga; Kobakozete Itono; Diazengwa Mpaka; Mampaka Mana Mouiny; Itio Momba

    1981-01-01

    During a lazy susan forty irradiation tube inspection with the specimen lifting device, the solenoid-operated specimen pick-up tool happened to be locked in the number fourteen position loading tube. The present paper describes the successful experiment which was carried out to solve a potential damaging situation for the safe and useful operation of the reactor. The first step in the investigation process was to ascertain what has indeed occurred in the reactor core to avoid any ill advised step which will worsen the situation. The alternatives were the following: a) The specimen tube was not lined with the loading tube; b) The lazy susan was not working properly due example to the fact that a roll pin in a drive shaft coupling inside the drive shaft tube has been broken; c) The pick-up tool has produced through the cleanout hole in the bottom of the specimen tube and engage the hole; d) The pick-up tool might have slided most of the way between the lazy susan and its housing. By moving up and down the pick-up tool and rotating back and forth the lazy susan it was possible to come to the conclusion that alternative c) was the most likely. It was not possible to release the pick-up tool because its engaging arms could not be activated as was often the case when lifting aluminium container

  9. Solenoid pick-up problem in the CREN-K Triga Mark 2 reactor

    Energy Technology Data Exchange (ETDEWEB)

    Malu wa Kalenga; Kobakozete Itono; Diazengwa Mpaka; Mampaka Mana Mouiny; Itio Momba (Commissariat des Sciences Nucleaires, Kinshasa (Zaire). Centre Regional d' Etudes Nucleaires)

    1981-01-01

    During a lazy susan forty irradiation tube inspection with the specimen lifting device, the solenoid-operated specimen pick-up tool happened to be locked in the number fourteen position loading tube. The present paper describes the successful experiment which was carried out to solve a potential damaging situation for the safe and useful operation of the reactor. The first step in the investigation process was to ascertain what has indeed occurred in the reactor core to avoid any ill advised step which will worsen the situation. The alternatives were the following: a) The specimen tube was not lined with the loading tube; b) The lazy susan was not working properly due example to the fact that a roll pin in a drive shaft coupling inside the drive shaft tube has been broken; c) The pick-up tool has produced through the cleanout hole in the bottom of the specimen tube and engage the hole; d) The pick-up tool might have slided most of the way between the lazy susan and its housing. By moving up and down the pick-up tool and rotating back and forth the lazy susan it was possible to come to the conclusion that alternative c) was the most likely. It was not possible to release the pick-up tool because its engaging arms could not be activated as was often the case when lifting aluminium container.

  10. Exact methods for time constrained routing and related scheduling problems

    DEFF Research Database (Denmark)

    Kohl, Niklas

    1995-01-01

    of customers. In the VRPTW customers must be serviced within a given time period - a so called time window. The objective can be to minimize operating costs (e.g. distance travelled), fixed costs (e.g. the number of vehicles needed) or a combination of these component costs. During the last decade optimization......This dissertation presents a number of optimization methods for the Vehicle Routing Problem with Time Windows (VRPTW). The VRPTW is a generalization of the well known capacity constrained Vehicle Routing Problem (VRP), where a fleet of vehicles based at a central depot must service a set...... of J?rnsten, Madsen and S?rensen (1986), which has been tested computationally by Halse (1992). Both methods decompose the problem into a series of time and capacity constrained shotest path problems. This yields a tight lower bound on the optimal objective, and the dual gap can often be closed...

  11. Siting of research reactors

    International Nuclear Information System (INIS)

    1987-01-01

    The purpose of this document is to develop criteria for siting and the site-related design basis for research reactors. The concepts presented in this document are intended as recommendations for new reactors and are not suggested for backfitting purposes for facilities already in existence. In siting research reactors serious consideration is given to minimizing the effects of the site on the reactor and the reactor on the site and the potential impact of the reactor on the environment. In this document guidance is first provided on the evaluation of the radiological impact of the installation under normal reactor operation and accident conditions. A classification of research reactors in groups is then proposed, together with a different approach for each group, to take into account the relevant safety problems associated with facilities of different characteristics. Guidance is also provided for both extreme natural events and for man-induced external events which could affect the safe operation of the reactor. Extreme natural events include earthquakes, flooding for river or coastal sites and extreme meteorological phenomena. The feasibility of emergency planning is finally considered for each group of reactors

  12. French energy research problems in relation to national energy goals

    International Nuclear Information System (INIS)

    Ferrari, A.

    1984-01-01

    There is a new view in energy planning: the new Government has firmly decided to enlarge the spectrum of energy technologies, to give more possibilities. Some new technologies if they reach a sufficient economic balance may be better than the ones used presently, and strict economic analysis shall be complemented by including external cost and taking into account the other considerations (political, social, etc.). The energy situation is serious and no technology should be dismissed: nuclear energy which with coal is one of the two sources of energy already abundant, cannot be discarded especially in a country like France, poor in fossil sources. France shall go on using nuclear energy and this means pursuing the development of the Fast Breeder Reactor Technology, because this is a unique insurance against possible future energy scarcity. Under strict nonproliferation conditions they shall also continue the effort to export nuclear units, using the expertise gained while implementing their own program

  13. Vessel-related problems in severe accidents, International Research Projects

    International Nuclear Information System (INIS)

    Figueras, J. M.

    2000-01-01

    The paper describes those most relevant aspects of research programmes and projects, on the behavior of vessel during severe accidents with partial or total reactor core fusion, performed during the last twenty years or still on-going projects, by countries or international organizations in the nuclear community, presenting the most important technical aspects, in particular the results achieved, as well as the financial and organisational aspects. The paper concludes that, throughout a joint effort of the international nuclear community, in which Spain has been present via private and public organizations, actually exist a reasonable technical and experimental knowledge of the vessel in case of severe accidents, but still there are aspects not fully solved which are the basis for continuing some programmes and for proposal of new ones. (Author)

  14. New trends in the evaluation and implementation of the safety-related operating experience associated with NRC-licensed reactors

    International Nuclear Information System (INIS)

    Michelson, C.; Heltemes, C.J.

    1981-01-01

    This article is an overview of the Nuclear Regulatory Commission program for the evaluation and dissemination of the safety-related operating experience associated with all NRC-licensed reactors. It discusses the historical background and past problems that led to the recent formation of NRC's Office for Analysis and Evaluation of Operational Data (AEOD) and details its activities, organization, staffing, and proposed analysis and evaluation methodology. The programs of industry organizations and nuclear plant licensees and the integration of foreign operating experience are included in the overview. The problems and limitations of the Licensee Event Report (LER) program and the Nuclear Plant Reliability Data system program are discussed. The AEOD analysis and evaluation methodology program includes some new improvements in the assessment of safety-related operating experience. Of particular note is the sequence coding and search procedure being developed by AEOD under a contract with the Nuclear Safety Information Center at the Oak Ridge National Laboratory. This computer-based retrieval system will have markedly improved search strategy capability for such items as commoncause failures or complex system interactions involving various failure sequences and other relationships associated with an event. The system retrieves failure data and information on the principal LER occurrence and on related component and system responses. The computer-generated Power Reactor Watch List enables AEOD to monitor all critical or unusual situations warranting close attention because of potential public health and safety. This listing is supported by a preestablished computer search strategy of the historical data base permitting identification of all past events and statistical information that are applicable to the situation being watched

  15. Feasibility study for fast reactor and related fuel cycle. Preliminary studies in 1998

    International Nuclear Information System (INIS)

    Hayafune, Hiroki; Enuma, Yasuhiro; Kubota, Kenichi; Yoshida, Masashi; Uno, Osamu; Ishikawa, Hiroyasu; Kobayashi, Jun; Umetsu, Youichiro; Ichimiya, Masakazu

    1999-10-01

    Prior to the feasibility study for fast reactors (FRs) starting from the 1999 fiscal year, planned in the medium and long-term program of JNC, preliminarily studies were performed on 'FR systems except sodium cooled MOX fueled reactors'. Small scale or module type reactors, heavy metal (Pb or Pb-Bi) cooled reactors, gas cooled reactors, light water cooled reactors, and molten salt reactors were studied on the basis of literature. They were evaluated from the viewpoint of the technical possibility (the structure integrity, earthquake resistance, safety, productivity, operability, maintenance repair, difficulty of the development), the long-term targets (market competitiveness as an energy system, utilization of uranium resources, reduction of radioactive waste, security of the non-proliferation), and developmental risk. As the result, the following concepts should be studied for future commercialized FRs. Small scale and module type reactor: Middle-sized reactor with an excellent economical efficiency. Small power reactor with a multipurpose design concept. Gas cooled reactor: CO2 gas cooled reactor, He gas cooled reactor. Heavy metal cooled reactor: Russian type lead cooled reactor. Light water cooled reactor: Light water cooled high converter reactor and super critical pressure light water cooled reactor. Molten salt reactor: Trichloride molten salt reactor which matches the U-Pu cycle. (author)

  16. Reactor operation

    CERN Document Server

    Shaw, J

    2013-01-01

    Reactor Operation covers the theoretical aspects and design information of nuclear reactors. This book is composed of nine chapters that also consider their control, calibration, and experimentation.The opening chapters present the general problems of reactor operation and the principles of reactor control and operation. The succeeding chapters deal with the instrumentation, start-up, pre-commissioning, and physical experiments of nuclear reactors. The remaining chapters are devoted to the control rod calibrations and temperature coefficient measurements in the reactor. These chapters also exp

  17. Reactor safeguards

    CERN Document Server

    Russell, Charles R

    1962-01-01

    Reactor Safeguards provides information for all who are interested in the subject of reactor safeguards. Much of the material is descriptive although some sections are written for the engineer or physicist directly concerned with hazards analysis or site selection problems. The book opens with an introductory chapter on radiation hazards, the construction of nuclear reactors, safety issues, and the operation of nuclear reactors. This is followed by separate chapters that discuss radioactive materials, reactor kinetics, control and safety systems, containment, safety features for water reactor

  18. The International conference on fast reactors and related fuel cycles: next generation nuclear systems for sustainable development. Book of abstracts

    International Nuclear Information System (INIS)

    2017-01-01

    The materials of the International Conference on Fast Reactors and Related Fuel Cycles (June 26-29, 2017, Yekaterinburg) are presented. The forum was organized by the IAEA with the assistance of Rosatom State Corporation. The theme of the conference: “The New Generation of Nuclear Systems for Sustainable Development”. About 700 specialists from more than 30 countries took part in the conference. The state and prospects for the development of the direction of fast reactors in countries dealing with this topic were discussed. A wide range of scientific issues covered the concepts of prospective reactors, reactor cores, fuel and fuel cycles, operation and decommissioning, safety, licensing, structural materials, industrial implementation [ru

  19. Pressurized water reactor fuel performance problems connected with fuel cladding corrosion processes

    International Nuclear Information System (INIS)

    Dobrevski, I.; Zaharieva, N.

    2008-01-01

    Generally, Pressurized Water Reactor (WWER, PWR) Fuel Element Performance is connected with fuel cladding corrosion and crud deposition processes. By transient to extended fuel cycles in nuclear power reactors, aiming to achieve higher burnup and better fuel utilization, the role of these processes increases significantly. This evolution modifies the chemical and electrochemical conditions in the reactor primary system, including change of fuel claddings' environment. The higher duty cores are always attended with increased boiling (sub-cooled nucleate boiling) mainly on the feed fuel assemblies. This boiling process on fuel cladding surfaces can cause different consequences on fuel element cladding's environment characteristics. In the case of boiling at the cladding surfaces without or with some cover of corrosion product deposition, the behavior of gases dissolved in water phase is strongly influenced by the vapor generation. The increase of vapor partial pressure will reduce the partial pressures of dissolved gases and will cause their stripping out. By these circumstances the concentrations of dissolved gases in cladding wall water layer can dramatically decrease, including also the case by which all dissolved gases to be stripped out. On the other hand it is known that the hydrogen is added to primary coolant in order to avoid the production of oxidants by radiolysis of water. It is clear that if boiling strips out dissolved hydrogen, the creation of oxidizing conditions at the cladding surfaces will be favored. In this case the local production of oxidants will be a result from local processes of water radiolysis, by which not only both oxygen (O 2 ) and hydrogen (H 2 ) but also hydrogen peroxide (H 2 O 2 ) will be produced. While these hydrogen and oxygen will be stripped out preferentially by boiling, the bigger part of hydrogen peroxide will remain in wall water phase and will act as the most important factor for creation of oxidizing conditions in fuel

  20. Guideline related to training and re-training of research reactor personnel

    International Nuclear Information System (INIS)

    1983-01-01

    The guideline, which entered into force on 1 July 1983, lays down training and re-training requirements to be met by research reactor personnel in the framework of the Radiation Protection Ordinance of 26 November 1969, the Regulation related to the Licensing of Nuclear Facilities of 21 June 1979, and the Regulation related to Further Education in the Field of Radiation Protection 27 January 1975. It contains the scope of application; the principles and objectives; the minimum requirements relating to technical qualification of plant managers, shift personnel, and responsible radiation protection officers; appointment and certification; the preservation of the technical qualification; and exceptional and transitional regulations

  1. Problems of making the laminar construction of the nuclear reactor safety hausing

    International Nuclear Information System (INIS)

    Ablewicz, Z.

    1980-01-01

    General specifications and operating conditions of a safety housing are followed by a characteristics of constructional materials and a description of basic problems connected with making the laminar structure of this housing. (author)

  2. NJOY-94, General ENDF/B Processing System for Reactor Design Problems

    International Nuclear Information System (INIS)

    1997-01-01

    1 - Description of program or function: The NJOY nuclear data processing system is a comprehensive computer code system for producing pointwise and multigroup cross sections and related quantities from ENDF/B evaluated nuclear data in the ENDF format, including the latest US library, ENDF/B-VI. The NJOY code works with neutrons, photons, and charged particles and produces libraries for a wide variety of particle transport and reactor analysis codes. It is capable of processing data in ENDF/B-4, ENDF/B-5, and ENDF/B-6 formats for evaluated data. Short descriptions of the different modules follow: RECONR Reconstructs pointwise cross sections from ENDF/B resonance parameters and interpolation schemes. BROADR Doppler broadens and thins pointwise cross sections. UNRESR Computes effective self-shielded pointwise cross sections in the unresolved-resonance region. HEATR Generates pointwise heat production cross sections and radiation-damage-energy production cross sections. THERMR Produces incoherent inelastic energy-to-energy matrices for free or bound scatterers, coherent elastic cross sections for hexagonal materials, and incoherent elastic cross sections. GROUPR Generates self-shielded multigroup cross sections, group- to-group neutron scattering matrices, and photon production matrices from pointwise input. GAMINR Calculates multigroup photon interaction cross sections and KERMA factors and group-to-group photon scattering matrices. ERRORR Produces multigroup covariance matrices from ENDF/B uncertainties. COVR Reads the output of ERRORR and performs covariance plotting and output-formatting operations. DTFR Formats multigroup data for transport codes such as DTF-IV and ANISN. CCCCR Formats multigroup data for the CCCC standard interface files ISOTXS, BRKOXS, and DLAYXS. MATXSR Formats multigroup data for the MATXS cross section interface file. ACER Prepares libraries for the Los Alamos continuous-energy Monte Carlo code MCNP. POWR Prepares libraries for the EPRI

  3. Light Water Reactor Sustainability Program Industry Application External Hazard Analyses Problem Statement

    Energy Technology Data Exchange (ETDEWEB)

    Szilard, Ronaldo Henriques [Idaho National Lab. (INL), Idaho Falls, ID (United States); Coleman, Justin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Smith, Curtis L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Prescott, Steven [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kammerer, Annie [Annie Kammerer Consulting, Rye, NH (United States); Youngblood, Robert [Idaho National Lab. (INL), Idaho Falls, ID (United States); Pope, Chad [Idaho State Univ., Pocatello, ID (United States)

    2015-07-01

    Risk-Informed Margin Management Industry Application on External Events. More specifically, combined events, seismically induced external flooding analyses for a generic nuclear power plant with a generic site soil, and generic power plant system and structure. The focus of this report is to define the problem above, set up the analysis, describe the methods to be used, tools to be applied to each problem, and data analysis and validation associated with the above.

  4. Status of food and raw milk supply and problem just after the reactor accident

    International Nuclear Information System (INIS)

    Hirakawa, Sachiko; Murakami, Kana; Yoshizawa, Nobuaki; Takizawa, Mari; Kawai, Masaki; Sato, Osamu; Takagi, Syunji; Nakamura, Takashi

    2014-01-01

    Iodine 131 was detected in the environment and the food such as vegetables, raw milk and tap water just after the reactor accident following the East Japan Great Earthquake occurred in March 11, 2011. This article investigated status of refuge of Fukushima residents, their dietary life and food distribution from March 11 to 31 just after the accident so as to reevaluate internal exposure dose with Iodine 131. Investigation results showed most of food taken by refugees was confirmed food stock or relief supplies outside from the disaster area and suggested food contaminated with Iodine 131 was not widely consumed and distributed due to limit to send designated vegetables, restriction of tap water intake, damaged distribution facilities and closing down of retail stores. Restriction of tap water intake was only applied partly, so this might cause internal exposure dose due to tap water. (T. Tanaka)

  5. Radioactivity analyses and detection limit problems of environmental surveillance at a gas-cooled reactor

    International Nuclear Information System (INIS)

    Johnson, J.E.; Johnson, J.A.

    1988-01-01

    The lower limit of detection (LLD) values required by the USNRC for nuclear power facilities are often difficult to attain even using state of the art detection systems, e.g. the required LLD for I-131 in air is 70 fCi/m 3 . For a gas-cooled reactor where I-131 has never been observed in effluents, occasional false positive values occur due to: Counting statistics using high resolution Ge(Li) detectors, contamination from nuclear medicine releases and spectrum analysis systematic error. Statistically negative concentration values are often observed. These measurements must be included in the estimation of true mean values. For this and other reasons, the frequency distributions of this and other reasons, the frequency distributions of measured values appear to be log-normal. Difficulties in stating the true means and standard deviations are discussed for these situations

  6. Stainless steels in boiling water reactors. Corrosion problems and possible solutions

    International Nuclear Information System (INIS)

    Combrade, P.; Desestret, A.; Leroy, F.; Coriou, H.

    1977-01-01

    In boiling water reactors, the heat-carrying water may have an up to 0.1 or even 0.2 ppm oxygen content, which can make it highly agressive at operating temperature for stainless steels subject to high physical stresses. Several metallurgical solutions can be considered, and in particular the use of stainless steels having a mixed austenitic-ferritic structure or of standard austenitic steels (18.10 or 18.10 Mo, such as AISI 304 and 316) with carefully controlled carbon and alloy element contents. The behavior of these steels during prolonged tests in water at 288 0 C with a 30 and even 100 ppm oxygen content turned out to be quite satisfactory [fr

  7. Summary of IEA-R1 research a reactor licensing related to its power increase from 2 to 10 MW

    International Nuclear Information System (INIS)

    1989-04-01

    This work is a summary of IEA-R1 research reactor licensing related to its power increase from 2 to 10 MW. It reports also safety requirements, fuel elements, and reactor control modifications inherent to power increase. (A.C.A.S.)

  8. Efficient parallel algorithms for string editing and related problems

    Science.gov (United States)

    Apostolico, Alberto; Atallah, Mikhail J.; Larmore, Lawrence; Mcfaddin, H. S.

    1988-01-01

    The string editing problem for input strings x and y consists of transforming x into y by performing a series of weighted edit operations on x of overall minimum cost. An edit operation on x can be the deletion of a symbol from x, the insertion of a symbol in x or the substitution of a symbol x with another symbol. This problem has a well known O((absolute value of x)(absolute value of y)) time sequential solution (25). The efficient Program Requirements Analysis Methods (PRAM) parallel algorithms for the string editing problem are given. If m = ((absolute value of x),(absolute value of y)) and n = max((absolute value of x),(absolute value of y)), then the CREW bound is O (log m log n) time with O (mn/log m) processors. In all algorithms, space is O (mn).

  9. The relationships between problem characteristics, achievement-related behaviors, and academic achievement in problem-based learning

    NARCIS (Netherlands)

    N. Sockalingam (Nachamma); J.I. Rotgans (Jerome); H.G. Schmidt (Henk)

    2011-01-01

    textabstractThis study investigated the influence of five problem characteristics on students' achievement-related classroom behaviors and academic achievement. Data from 5,949 polytechnic students in PBL curricula across 170 courses were analyzed by means of path analysis. The five problem

  10. Task types and error types involved in the human-related unplanned reactor trip events

    International Nuclear Information System (INIS)

    Kim, Jae Whan; Park, Jin Kyun

    2008-01-01

    In this paper, the contribution of task types and error types involved in the human-related unplanned reactor trip events that have occurred between 1986 and 2006 in Korean nuclear power plants are analysed in order to establish a strategy for reducing the human-related unplanned reactor trips. Classification systems for the task types, error modes, and cognitive functions are developed or adopted from the currently available taxonomies, and the relevant information is extracted from the event reports or judged on the basis of an event description. According to the analyses from this study, the contributions of the task types are as follows: corrective maintenance (25.7%), planned maintenance (22.8%), planned operation (19.8%), periodic preventive maintenance (14.9%), response to a transient (9.9%), and design/manufacturing/installation (6.9%). According to the analysis of the error modes, error modes such as control failure (22.2%), wrong object (18.5%), omission (14.8%), wrong action (11.1%), and inadequate (8.3%) take up about 75% of the total unplanned trip events. The analysis of the cognitive functions involved in the events indicated that the planning function had the highest contribution (46.7%) to the human actions leading to unplanned reactor trips. This analysis concludes that in order to significantly reduce human-induced or human-related unplanned reactor trips, an aide system (in support of maintenance personnel) for evaluating possible (negative) impacts of planned actions or erroneous actions as well as an appropriate human error prediction technique, should be developed

  11. Task types and error types involved in the human-related unplanned reactor trip events

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Whan; Park, Jin Kyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-12-15

    In this paper, the contribution of task types and error types involved in the human-related unplanned reactor trip events that have occurred between 1986 and 2006 in Korean nuclear power plants are analysed in order to establish a strategy for reducing the human-related unplanned reactor trips. Classification systems for the task types, error modes, and cognitive functions are developed or adopted from the currently available taxonomies, and the relevant information is extracted from the event reports or judged on the basis of an event description. According to the analyses from this study, the contributions of the task types are as follows: corrective maintenance (25.7%), planned maintenance (22.8%), planned operation (19.8%), periodic preventive maintenance (14.9%), response to a transient (9.9%), and design/manufacturing/installation (6.9%). According to the analysis of the error modes, error modes such as control failure (22.2%), wrong object (18.5%), omission (14.8%), wrong action (11.1%), and inadequate (8.3%) take up about 75% of the total unplanned trip events. The analysis of the cognitive functions involved in the events indicated that the planning function had the highest contribution (46.7%) to the human actions leading to unplanned reactor trips. This analysis concludes that in order to significantly reduce human-induced or human-related unplanned reactor trips, an aide system (in support of maintenance personnel) for evaluating possible (negative) impacts of planned actions or erroneous actions as well as an appropriate human error prediction technique, should be developed.

  12. Environmental problems related to winter traffic safety conditions

    OpenAIRE

    Hääl, Maire-Liis; Sürje, Peep

    2006-01-01

    The changeable Nordic climate has added problems to road maintenance and the environment to ensure traffic safety under winter conditions. The widespread use of salt (NaCl) for snow and ice removal from roads has resulted in environmental impacts in many areas. Some of the problems associated with the use of NaCl are the corrosion of bridges, road surfaces and vehicles and damage to roadside vegetation and aquatic system that are affected by water from de-iced roads. Accumulation of hard meta...

  13. On solution to the problem of reactor kinetics with delayed neutrons by Monte Carlo method

    International Nuclear Information System (INIS)

    Kyncl, Jan

    2013-07-01

    The initial value problem is addressed for the neutron transport equation and for the system of equations that describe the behaviour of emitters of delayed neutrons. Examination of the solution to this problem is based on several main assumptions concerning the behaviour of macroscopic effective cross-sections describing the reaction of the neutron with the medium, the temperature of medium and the remaining parameters of the equations. Formulation of these assumptions is adequately general and is in agreement with the properties of all known models of the physical quantities involved. Among others, the assumptions admit dependence of the macroscopic effective cross-sections and temperature on spatial coordinates and time that can be arbitrary to a great extent. The problem starts from a set of integro-differential equations. This problem is first transposed into the equivalent problem of solving a linear integral equation for neutron flux. This integral equation is solved by the method of successive iterations and its uniqueness is demonstrated. Numeric solution to the integral equation by Monte Carlo method consists in finding a functional of the exact solution. For this, a random process is set up and some random variables are proposed. Then it is demonstrated that each of these variables is an unbiased estimator of that functional. (author)

  14. Delayed Stochastic Linear-Quadratic Control Problem and Related Applications

    Directory of Open Access Journals (Sweden)

    Li Chen

    2012-01-01

    stochastic differential equations (FBSDEs with Itô’s stochastic delay equations as forward equations and anticipated backward stochastic differential equations as backward equations. Especially, we present the optimal feedback regulator for the time delay system via a new type of Riccati equations and also apply to a population optimal control problem.

  15. Income inequality, alcohol use, and alcohol-related problems.

    Science.gov (United States)

    Karriker-Jaffe, Katherine J; Roberts, Sarah C M; Bond, Jason

    2013-04-01

    We examined the relationship between state-level income inequality and alcohol outcomes and sought to determine whether associations of inequality with alcohol consumption and problems would be more evident with between-race inequality measures than with the Gini coefficient. We also sought to determine whether inequality would be most detrimental for disadvantaged individuals. Data from 2 nationally representative samples of adults (n = 13,997) from the 2000 and 2005 National Alcohol Surveys were merged with state-level inequality and neighborhood disadvantage indicators from the 2000 US Census. We measured income inequality using the Gini coefficient and between-race poverty ratios (Black-White and Hispanic-White). Multilevel models accounted for clustering of respondents within states. Inequality measured by poverty ratios was positively associated with light and heavy drinking. Associations between poverty ratios and alcohol problems were strongest for Blacks and Hispanics compared with Whites. Household poverty did not moderate associations with income inequality. Poverty ratios were associated with alcohol use and problems, whereas overall income inequality was not. Higher levels of alcohol problems in high-inequality states may be partly due to social context.

  16. Computer Use and Vision‑Related Problems Among University ...

    African Journals Online (AJOL)

    and adjusted OR was calculated using the multiple logistic regression. Results: The ... Nearly 72% of students reported frequent interruption of computer work. Headache ... procedure (non-probability sampling) recruiting 250 .... Table 1: Percentage distribution of visual problems among different genders and ethnic groups.

  17. Mental Health Problems and Related Factors in Ecuadorian College Students

    Directory of Open Access Journals (Sweden)

    Claudia Torres

    2017-05-01

    Full Text Available Although the mental health problems of college students have been the subject of increasing research, there are no studies about its prevalence in Ecuadorian college students. The aim of this study was to determine the mental health problems and their associated factors in Ecuadorian freshmen university students. A sample of 1092 students (53.7% women; mean age = 18.3 years were recruited from the Technical Particular University of Loja (Ecuador. Socio-demographic, academic, and clinical characteristics were gathered, as well as information on the participants’ mental health through a number of mental health screens. Prevalence of positive screens was 6.2% for prevalence of major depressive episodes, 0.02% for generalized anxiety disorders, 2.2% for panic disorders, 32.0% for eating disorders, 13.1% for suicidal risk. Mental health problems were significantly associated with sex, area of study, self-esteem, social support, personality and histories of mental health problems. The findings offer a starting point for identifying useful factors to target prevention and intervention strategies aimed at university students.

  18. Mental Health Problems and Related Factors in Ecuadorian College Students.

    Science.gov (United States)

    Torres, Claudia; Otero, Patricia; Bustamante, Byron; Blanco, Vanessa; Díaz, Olga; Vázquez, Fernando L

    2017-05-15

    Although the mental health problems of college students have been the subject of increasing research, there are no studies about its prevalence in Ecuadorian college students. The aim of this study was to determine the mental health problems and their associated factors in Ecuadorian freshmen university students. A sample of 1092 students (53.7% women; mean age = 18.3 years) were recruited from the Technical Particular University of Loja (Ecuador). Socio-demographic, academic, and clinical characteristics were gathered, as well as information on the participants' mental health through a number of mental health screens. Prevalence of positive screens was 6.2% for prevalence of major depressive episodes, 0.02% for generalized anxiety disorders, 2.2% for panic disorders, 32.0% for eating disorders, 13.1% for suicidal risk. Mental health problems were significantly associated with sex, area of study, self-esteem, social support, personality and histories of mental health problems. The findings offer a starting point for identifying useful factors to target prevention and intervention strategies aimed at university students.

  19. Language and Communication-Related Problems of Aviation Safety.

    Science.gov (United States)

    Cushing, Steven

    A study of the problems posed by the use of natural language in various aspects of aviation is presented. The study, part of a larger investigation of the feasibility of voice input/output interfaces for communication in aviation, looks at representative real examples of accidents and near misses resulting from language confusions and omissions.…

  20. Dissimilar welding in nuclear reactors: review of the main aspects related to dissimilar welding of carbon steel and stainless steel with addition of nickel alloys

    International Nuclear Information System (INIS)

    Ribeiro, Vladimir Soler

    2015-01-01

    This work presents a review of the literature about Stress Corrosion Cracking, which is one of the main damage mechanisms that affect PWR and BWR type nuclear reactor. It deals with issues related to one of the sources of the problem, which are the trative residual stress caused by the thermal cycle of welding. It also addressed measurement techniques of residual stresses, with emphasis on technique the center hole drilling. It is shown that, once found the problem, there are means to mitigate the damage, which allow prolonging the life of the component. (author)

  1. Empirical relations for tensile properties of austenitic stainless steels irradiated in mixed-spectrum reactors

    International Nuclear Information System (INIS)

    Grossbeck, M.L.

    1991-01-01

    An assessment has been made of available tensile property data relevant to the design of fusion reactors, especially near term devices expected to operate at lower temperatures than power reactors. Empirical relations have been developed for the tensile properties as a functions of irradiation temperature for neutron exposures of 10-15, 20, 30, and 50 dpa. It was found that yield strength depends little on the particular austenitic alloy and little on the helium concentration. Strength depends upon initial condition of the alloy only for exposures of less than 30 dpa. Uniform elongation was found to be more sensitive to alloy and condition. It was also more sensitive than strength to helium level. However, below 500deg C, helium only appeared to have an efect at 10-15 dpa. At higher temperatures, helium embrittlement was apparent, and its threshold temperature decreased with increasing neutron exposure level. (orig.)

  2. Investigation of fluid flow in various geometries related to nuclear reactor using PIV system

    International Nuclear Information System (INIS)

    Kansal, A.K.; Maheshwari, N.K.; Singh, R.K.; Vijayan, P.K.; Saha, D.; Singh, R.K.; Joshi, V.M.

    2011-01-01

    Particle Image Velocimetry (PIV) is a non-intrusive technique for simultaneously measuring the velocities at many points in a fluid flow. The PIV system used is comprised of Nd:YAG laser source, CCD (Charged Coupled Device) camera, timing controller (to control the laser and camera) and software used for analyzing the flow velocities. Several case studies related to nuclear reactor were performed with the PIV system. Some of the cases like flow in circular tube, submerged jet, natural convection in a water pool, flow field of moderator inlet diffuser of 500 MWe Pressurised Heavy Water Reactor (PHWR) and fluidic flow control device (FFCD) used in advanced accumulator of Emergency Core Cooling System (ECCS) have been studied using PIV system. Theoretical studies have been performed and comparisons with PIV results are also given in the present studies. (author)

  3. General design and main problems of a gas-heavy-water power reactor contained in a pressure vessel

    International Nuclear Information System (INIS)

    Roche, R.; Gaudez, J.C.

    1964-01-01

    In the framework of research carried out on a CO 2 -cooled power reactor moderated by heavy water, the so-called 'pressure vessel' solution involves the total integration of the core, of the primary circuit (exchanges and blowers) and of the fuel handling machine inside a single, strong, sealed vessel made of pre-stressed concrete. A vertical design has been chosen: the handling 'attic' is placed above the core, the exchanges being underneath. This solution makes it possible to standardize the type of reactor which is moderated by heavy-water or graphite and cooled by a downward stream of carbon dioxide gas; it has certain advantages and disadvantages with respect to the pressure tube solution and these are considered in detail in this report. Extrapolation presents in particular.problems due specifically to the heavy water (for example its cooling,its purification, the balancing of the pressures of the heavy water and of the gas, the assembling of the internal structures, the height of the attic, etc. (authors) [fr

  4. Gambling behaviors and psychopathology related to Attention-Deficit/Hyperactivity Disorder (ADHD) in problem and non-problem adult gamblers.

    Science.gov (United States)

    Fatseas, Melina; Alexandre, Jean-Marc; Vénisse, Jean-Luc; Romo, Lucia; Valleur, Marc; Magalon, David; Chéreau-Boudet, Isabelle; Luquiens, Amandine; Guilleux, Alice; Groupe Jeu; Challet-Bouju, Gaëlle; Grall-Bronnec, Marie

    2016-05-30

    Previous studies showed that Pathological Gambling and Attention Deficit/Hyperactivity Disorder (ADHD) often co-occur. The aim of this study was to examine whether ADHD is associated with specific severity patterns in terms of gambling behavior, psychopathology and personality traits. 599 problem and non-problem-gamblers were recruited in addiction clinics and gambling places in France. Subjects were assessed with the Wender-Utah Rating Scale-Child, the Adult ADHD Self-Report Scale, the Mini International Neuropsychiatric Interview, the Temperament and Character Inventory, the South Oaks Gambling Screen and questionnaires assessing gambling related cognitive distortions and gambling habits. 20.7% (n=124) of gamblers were screened positive for lifetime or current ADHD. Results from the multivariate analysis showed that ADHD was associated with a higher severity of gambling-related problems and with more psychiatric comorbidity. Among problem gamblers, subjects with history of ADHD were also at higher risk for unemployment, psychiatric comorbidity and specific dysfunctional personality traits. This study supports the link between gambling related problems and ADHD in a large sample of problem and non-problem gamblers, including problem-gamblers not seeking treatment. This points out the necessity to consider this disorder in the prevention and in the treatment of pathological gambling. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. Convergence problems associated with the iteration of adjoint equations in nuclear reactor theory

    International Nuclear Information System (INIS)

    Ngcobo, E.

    2003-01-01

    Convergence problems associated with the iteration of adjoint equations based on two-group neutron diffusion theory approximations in slab geometry are considered. For this purpose first-order variational techniques are adopted to minimise numerical errors involved. The importance of deriving the adjoint source from a breeding ratio is illustrated. The results obtained are consistent with the expected improvement in accuracy

  6. Set problem teaching methods used in the course of Control and protection systems of nuclear reactors

    International Nuclear Information System (INIS)

    Korolev, V.V.

    1995-01-01

    Some results of pedagogical investigations on the application of the sep problem teaching method at the Obninsk Institute of Nuclear Power Engineering are presented. The method aims at improving the quality of training operation and maintenance personnel for nuclear power plants

  7. The problem of using trade secrets in economic relations

    Directory of Open Access Journals (Sweden)

    А. О. Олефір

    2015-05-01

    Full Text Available Problem setting. In a market economy and increased competition between enterprises become increasingly important concepts such as business information, trade secrets, know-how, confidential information, the information with restricted access. Given the fact that only one patent protection is unable to meet the needs of researchers, in addition to formal public protection and secured legal means we would like to pay attention at private legal measures, particular, the mode of trade secrets. Recent research and publications analysis. Different aspects of the protection of trade secrets were investigated by specialists such as G. Androschuk, J. Berzhye, I. Davydov, O. Davydyuk, D. Zadyhaylo, P. Kraynov, G. Nikiforov, S. Nikiforov, V. Rubanov, E. Solovyov, L. Hoffman, V. Chaplygin, A. Cherniavsky and others. However, at present there is a lack of comprehensive research of this legal phenomenon, equally useful for innovators and businesses that actively protect corporate security. Paper objective. This article is planned to determine the legal characteristics, structural elements and mechanisms by which the use of trade secrets in business have a positive impact on innovation development and corporate security entities. Paper main body. On the basis of requirements of Art. 505 Civil Code of Ukraine and art. 39 of the TRIPS Agreement we formulated commercial information signs under which it receives legal protection as an object of intellectual property: (1 privacy (real or potential in the sense that it is as a whole or in a precise combination of aggregate and its components are not generally known or available to persons in the circles that normally deal with such information; (2 commercial value (not purely industrial or industrial, due to its secrecy; this information is unknown to others, which is a commercial interest; (3 the lawful holder of the information provides active special measures (technical, organizational, legal to preserve secrecy

  8. Open Problems Related to the Hurwitz Stability of Polynomials Segments

    Directory of Open Access Journals (Sweden)

    Baltazar Aguirre-Hernández

    2018-01-01

    Full Text Available In the framework of robust stability analysis of linear systems, the development of techniques and methods that help to obtain necessary and sufficient conditions to determine stability of convex combinations of polynomials is paramount. In this paper, knowing that Hurwitz polynomials set is not a convex set, a brief overview of some results and open problems concerning the stability of the convex combinations of Hurwitz polynomials is then provided.

  9. The global existence problem and cosmic censorship in general relativity

    International Nuclear Information System (INIS)

    Moncrief, V.; Eardley, D.M.

    1981-01-01

    Two global existence conjectures for the Einstein equations are formulated and their relevance to the cosmic censorship conjecture discussed. It is argued that the reformulation of the cosmic censorship conjecture as a global existence problem renders it more amenable to direct analytical attack. To demonstrate the facility of this approach the cosmological version of the global existence conjecture is proved for the Gowdy spacetimes on T 3 X R. (author)

  10. Problems raised by the results of the German reactor risk study

    International Nuclear Information System (INIS)

    Huebschmann, W.G.; Vogt, S.

    1982-01-01

    The main subject of the German Reactor Risk Study is the assessment of the collective risk to the public due to the nuclear power plant operation - particularly due to uncontrolled accidents - in the Federal Republic of Germany. Whereas the collective risk is reasonably small as compared to other risks, the study also revealed the low probability end of maximum consequences, which are large enough - although extremely improbable - as to be termed catastrophic. It is shown, however, that the maximum number of early fatalities is strongly dependent on some conservative assumptions and on roughly averaged parameters. The results of recent research work suggest for example that the steam explosion can be neglected and the chemical reaction of radioiodine in the containment should be taken into account. The activity deposition on the ground should be simulated more realistically if single cases such as the maximum are to be evaluated. The possible margin of conservatism of the maximum consequences is shown to be more than one order of magnitude. (author)

  11. Nuclear reactor kinetics and control

    International Nuclear Information System (INIS)

    Lewins, J.

    1978-01-01

    A consistent, integrated account of modern developments in the study of nuclear reactor kinetics and the problem of their efficient and safe control. It aims to prepare the student for advanced study and research or practical work in the field. Special features include treatments of noise theory, reliability theory and safety related studies. It covers all aspects of the operation and control of nuclear reactors, power and research and is complete in providing physical data methods of calculation and solution including questions of equipment reliability. The work uses illustrations of the main types of reactors in use in the UK, USA and Europe. Each chapter contains problems and worked examples suitable for course work and study. The subject is covered in chapters, entitled: introductory review; neutron and precursor equations; elementary solutions at low power; linear reactor process dynamics with feedback; power reactor control systems; fluctuations and reactor noise; safety and reliability; nonlinear systems (safety and control); analogue computing. (author)

  12. Research reactors - an overview

    International Nuclear Information System (INIS)

    West, C.D.

    1997-01-01

    A broad overview of different types of research and type reactors is provided in this paper. Reactor designs and operating conditions are briefly described for four reactors. The reactor types described include swimming pool reactors, the High Flux Isotope Reactor, the Mark I TRIGA reactor, and the Advanced Neutron Source reactor. Emphasis in the descriptions is placed on safety-related features of the reactors. 7 refs., 7 figs., 2 tabs

  13. General remarks on fast neutron reactor physics

    International Nuclear Information System (INIS)

    Barre, J.Y.

    1980-01-01

    The main aspects of fast reactor physics, presented in these lecture notes, are restricted to LMFBR's. The emphasis is placed on the core neutronic balance and the burn-up problems. After a brief description of the power reactor main components and of the fast reactor chronology, the fundamental parameters of the one-group neutronic balance are briefly reviewed. Then the neutronic burn-up problems related to the Pu production and to the doubling time are considered

  14. Fluid history computation methods for reactor safeguards problems using MNODE computer program

    International Nuclear Information System (INIS)

    Huang, Y.S.; Savery, C.W.

    1976-10-01

    A method for predicting the pressure-temperature histories of air, water liquid, and vapor flowing in a zoned containment as a result of high energy pipe rupture is described. The computer code, MNODE, has been developed for 12 connected control volumes and 24 inertia flow paths. Predictions by the code are compared with the results of an analytical gas dynamic problem, semiscale blowdown experiments, full scale MARVIKEN test results, Battelle-Frankfurt model PWR containment test data. The MNODE solutions to NRC/AEC subcompartment benchmark problems are also compared with results predicted by other computer codes such as RELAP-3, FLASH-2, CONTEMPT-PS. The analytical consideration is consistent with Section 6.2.1.2 of the Standard Format (Rev. 2) issued by U.S. Nuclear Regulatory Commission in September 1975

  15. An application of reactor noise techniques to neutron transport problems in a random medium

    International Nuclear Information System (INIS)

    Sahni, D.C.

    1989-01-01

    Neutron transport problems in a random medium are considered by defining a joint Markov process describing the fluctuations of one neutron population and the random changes in the medium. Backward Chapman-Kolmogorov equations are derived which yield an adjoint transport equation for the average neutron density. It is shown that this average density also satisfied the direct transport equation as given by the phenomenological model. (author)

  16. Numerical analysis of impact-penetration problems for nuclear reactor safety

    International Nuclear Information System (INIS)

    Dubois, J.J.; Chedmail, J.F.; Bianchini, J.C.

    1977-01-01

    This paper discusses the finite element and finite difference analysis of two impact penetration problems, namely a fuel cask drop on a foundation slab and a missile penetration into a reinforced concrete structure. For a realistic detailed analysis, advanced techniques were required in the following areas: reinforced concrete simulation; remeshing algorithms for penetration induced distortions; boundary condition. The fuel cask drop on a concrete slab generates complex elasto plastic waves which propagate towards the pool where tensile cracks might appear. The problem is analysed in two steps: calculation of the energy absorbed locally around the impacted area; calculation of the three dimensional wave propagation towards the pool. For the analysis of missile penetration problems, two examples are shown: a 3000 kg missile with a velocity of 132 m/s penetrates a 1.2 m thick concrete wall (PAM-GDYNS) and a 3600 kg missile with a velocity of 90 m/s (F.D. Program HEMP-ESI) penetrates a wall at a floor level. For the second case, the computed impact-penetration mechanism is

  17. Advancement in reactor coolant chemistry management programs and related technology development in Taiwan

    International Nuclear Information System (INIS)

    Huang, C.S.; Lin, Chien C.

    2000-01-01

    Taiwan Power Company (TPC) has three nuclear power plants in operation with a total capacity of 51 GWe, contributing about 30% of electricity generation in Taiwan. The first two plants, Chinshan (CSNPP) and Kuosheng (KSNPP), are boiling water reactor plants, and the third one, Maanshan (MASNPP), is a pressurized water reactor plant. Each plant has two identical reactors. As many nuclear power plant operators worldwide, TPC is committed to operate the plants efficiently, economically, and safely. TPC has developed and implemented several chemistry improvement programs in recent years to improve the coolant chemistry in order to ( l ) protect structure materials from corrosion, (2) reduce radiation exposures to workers and (3) reduce radwaste production and radiation release to the environment. This paper describes TPC's experience in some water chemistry management, radwaste reduction and radiation exposure control programs. Future programs under planning, including implementation of hydrogen water chemistry (HWC) in BWRs, installation of condensate pre-filters, and development of on-line water chemistry monitoring system, are also be briefly discussed. In addition, some material related research and development programs will also be presented. (author)

  18. Current problems of foreign practice-related educational psychology

    Directory of Open Access Journals (Sweden)

    A.D. Andreeva

    2012-09-01

    Full Text Available The article regards the questions of scientific-methodological provision of psychologist’s activity in an educational settlement which are urgent for the activity of practical educational psychologist in Russia as well. The presented information concerns the psychologist’s particular strands of work which can be both developing (development of ABM and psycho-correcting (reasons and forms of school phobias, bullying displays, lying. The ethical problems of psychologist’s work with families namely in case of the parent-child conflicts is also reviewed in the article.

  19. Actual problems of accession in relation with library statistics

    Directory of Open Access Journals (Sweden)

    Tereza Poličnik-Čermelj

    2010-01-01

    Full Text Available Accession is the process of recording bibliographic units in an accession register. Typically,library materials are acquired by purchase, exchange, gift or legal deposit. How-ever, COBISS (Cooperative Online Bibliographic System and Services Holdings software module includes some additional methods of acquisition which causes problems in gathering and presenting statistical data on local holdings. The article explains how to record holdings of different types of library materials and how to record retrospective collections. It describes necessary procedures in case the codes that define the publication pattern of the holdings are changed with special attention to integrating resources. Procedures of accession and circulation of bound materials, supplementary materials, teaching sets, multi parts, multimedia and collection level catalogue records are described. The attention is given to errors in recording lost item replacements and to the problems of circulation of certain types of library materials. The author also suggests how to record remote electronic resources. It is recommended to verify holdings data before the accession register is generated. The relevant and credible statistical data on collection development can only be created by librarians with sufficient acquisition and cataloguing skills.

  20. Hot cell works and related irradiation tests in fission reactor for development of new materials for nuclear application

    International Nuclear Information System (INIS)

    Shikama, Tatsuo

    1999-01-01

    Present status of research works in Oarai Branch, Institute for Materials Research, Tohoku University, utilizing Japan Materials Testing Reactor and related hot cells will be described.Topics are mainly related with nuclear materials studies, excluding fissile materials, which is mainly aiming for development of materials for advanced nuclear systems such as a nuclear fusion reactor. Conflict between traditional and routined procedures and new demands will be described and future perspective is discussed. (author)

  1. 40 Dynamics of Foreign Trade and Trade Relation Problems: Policy ...

    African Journals Online (AJOL)

    FIRST LADY

    2011-01-18

    Jan 18, 2011 ... bounty of material good, but also of intellectual and cultural capital, an .... of market, increased investment and development of other sectors of the .... battered public image that has had an impinging effect on external relations.

  2. Bibliography on the stochastic processes in plasma and related problems

    International Nuclear Information System (INIS)

    Polovin, R.V.

    1976-01-01

    Stochastic processes in plasma and related matters. The bibliography contains 500 references and was compiled from the open literature only. Some references are annotated or completed with short abstracts. There are subject and authors indexes

  3. Relative information entropy in cosmology: The problem of information entanglement

    Energy Technology Data Exchange (ETDEWEB)

    Czinner, Viktor G., E-mail: czinner.viktor@wigner.mta.hu [Centro de Matemática, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); HAS Wigner Research Centre for Physics, H-1525 Budapest, P.O. Box 49 (Hungary); Mena, Filipe C., E-mail: fmena@math.uminho.pt [Centro de Matemática, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2016-07-10

    The necessary information to distinguish a local inhomogeneous mass density field from its spatial average on a compact domain of the universe can be measured by relative information entropy. The Kullback–Leibler (KL) formula arises very naturally in this context, however, it provides a very complicated way to compute the mutual information between spatially separated but causally connected regions of the universe in a realistic, inhomogeneous model. To circumvent this issue, by considering a parametric extension of the KL measure, we develop a simple model to describe the mutual information which is entangled via the gravitational field equations. We show that the Tsallis relative entropy can be a good approximation in the case of small inhomogeneities, and for measuring the independent relative information inside the domain, we propose the Rényi relative entropy formula.

  4. China's tax system relatively benign, but problems remain

    International Nuclear Information System (INIS)

    Cannon, M.

    1994-01-01

    Recent developments in China's oil market have reignited the interest of multinational oil and gas companies in China. New onshore and offshore blocks are being granted, and the Tarim basin has been opened to foreign participation for the first time. Foreign participation is also being sought in refining and other downstream areas. Though Chinese officials have long been viewed as difficult negotiators, the tax provisions applicable to oil and gas exploration and production in China are some of the more generous in the area. This article describes some of the relevant features of the system and some of the problem areas. The paper describes production sharing contracts, applicable taxes, gross income determination, taxable income, tax consolidation, overseas charges, and withholding taxes on payments to subcontractors and employees

  5. A RELATIONAL DATABASE APPROACH TO THE JOB SHOP SCHEDULING PROBLEM

    Directory of Open Access Journals (Sweden)

    P. Lindeque

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: This paper will attempt to illuminate the advantages of an approach to the job shop scheduling problem using priority based search algorithms and database technology. It will use as basis a system developed for and implemented at a large manufacturing plant. The paper will also attempt to make some predictions as to future developments in these techniques and look at the possibility of including new technologies such as expert systems.

    AFRIKAANSE OPSOMMING: Die voordele en toepaslikheid van prioriteits-gebaseerde soek-algoritmes en databasisstelsels op die taakwerkswinkelprobleem sal in hierdie artikel uitgelig word. 'n Stelsel wat by 'n groot vervaardigingsonderneming geimplementeer is, sal as uitgangspunt gebruik word. Toekomstige ontwikkelings in bogenoemde tegnieke en die moontlike insluiting van ekspertstelsels sal ook ondersoek word.

  6. Closed orbit related problems: Correction, feedback, and analysis

    International Nuclear Information System (INIS)

    Bozoki, E.S.

    1995-01-01

    Orbit correction - moving the orbit to a desired orbit, orbit stability - keeping the orbit on the desired orbit using feedback to filter out unwanted noise, and orbit analysis - to learn more about the model of the machine, are strongly interrelated. They are the three facets of the same problem. The better one knows the model of the machine, the better the predictions that can be made on the behavior of the machine (inverse modeling) and the more accurately one can control the machine. On the other hand, one of the tools to learn more about the machine (modeling) is to study and analyze the orbit response to open-quotes kicks.close quotes

  7. Pellet acceleration studies relating to the refuelling of a steady-state fusion reactor

    International Nuclear Information System (INIS)

    Dimock, D.; Jensen, K.; Jensen, V.O.; Joergensen, L.W.; Pecseli, H.L.; Soerensen, H.; Oester, F.

    1975-11-01

    Several methods for refuelling a steady state-fusion reactor have been proposed, and the pellet method seems advantageous if the pellet can be accelerated to the necessary velocity. A study group was formed to analyze this acceleration problem. Two pellet velocity values were considered: 10 4 m/s and 300 m/s. A pellet velocity of 10 4 m/s may be suitable in the case of a reactor, whereas 300 m/s is believed to be a reasonable velocity at which to perform realistic ablation experiments in the near future. A pneumatic acceleration method was found promising. The pressure is either supplied separately or by evaporation of a part of the pellet. In the latter case, a spark behind the pellet should provide the evoporation and the necessary heating of the driving gas. A preliminary test at room temperature with pellets made of beeswax (the density being ten times that of solid hydrogen, and plastic properties similar to those of solid hydrogen) resulted in a pellet velocity of 100 m/s at a modest value of the energy supplied to the spark. (Auth.)

  8. Optimization Problem of Thermal Field on Surface of Revolving Susceptor in Vapor-Phase Epitaxy Reactor

    Science.gov (United States)

    Zhilenkov, A. A.; Chernyi, S. G.; Nyrkov, A. P.; Sokolov, S. S.

    2017-10-01

    Nitrides of group III elements are a very suitable basis for deriving light-emitting devices with the radiating modes lengths of 200-600 nm. The use of such semiconductors allows obtaining full-color RGB light sources, increasing record density of a digital data storage device, getting high-capacity and efficient sources of white light. Electronic properties of such semi-conductors allow using them as a basis for high-power and high-frequency transistors and other electronic devices, the specifications of which are competitive with those of SiC-based devices. Only since 2000, the technology of cultivation of crystals III-N of group has come to the level of wide recognition by both abstract science, and the industry that has led to the creation of the multi-billion dollar market. And this is despite a rather low level of development of the production technology of devices on the basis of III-N of materials. The progress that has happened in the last decade requires the solution of the main problem, constraining further development of this technology today - ensuring cultivation of III-N structures of necessary quality. For this purpose, it is necessary to solve problems of the analysis and optimization of processes in installations of epitaxial growth, and, as a result, optimization of its constructions.

  9. Alcohol- and drug-related absenteeism: a costly problem.

    Science.gov (United States)

    Roche, Ann; Pidd, Ken; Kostadinov, Victoria

    2016-06-01

    Absenteeism related to alcohol and other drug (AOD) use can place a substantial burden on businesses and society. This study estimated the cost of AOD-related absenteeism in Australia using a nationally representative dataset. A secondary analysis of the 2013 National Drug Strategy Household Survey (n=12,196) was undertaken. Two measures of AOD-related absenteeism were used: participants' self-reported absence due to AOD use (M1); and the mean difference in absence due to any illness/injury for AOD users compared to abstainers (M2). Both figures were multiplied by $267.70 (average day's wage in 2013 plus 20% on-costs) to estimate associated costs. M1 resulted in an estimation of 2.5 million days lost annually due to AOD use, at a cost of more than $680 million. M2 resulted in an estimation of almost 11.5 million days lost, at a cost of $3 billion. AOD-related absenteeism represents a significant and preventable impost upon Australian businesses. Workplaces should implement evidence-based interventions to promote healthy employee behaviour and reduce AOD-related absenteeism. © 2015 Public Health Association of Australia.

  10. Environmental problems relating to uranium mining and milling

    International Nuclear Information System (INIS)

    Friedman, F.B.

    1979-01-01

    The regulations of the mining and milling of uranium as they relate to the environment are discussed. The industry is primarily under the jurisdiction of the federal government and administered by the Nuclear Regulatory Commission (NRC). This authority can in some instances be relegated to the states. Certain areas of jurisdiction have been given over to Environmental Protection Agency (EPA) by the courts. The Safe Drinking Water Act is discussed as it relates to in situ leach mining. The role of the Department of Interior in the regulating of uranium mining, as described in the Federal Land Policy Management Act of 1976, is discussed. The requirement for environmental impact statements prior to licensing by the NRC or the individual states is also discussed. Air quality and radioactive waste disposal as they relate to uranium mining are also discussed

  11. Analysis of events related to cracks and leaks in the reactor coolant pressure boundary

    Energy Technology Data Exchange (ETDEWEB)

    Ballesteros, Antonio, E-mail: Antonio.Ballesteros-Avila@ec.europa.eu [JRC-IET: Institute for Energy and Transport of the Joint Research Centre of the European Commission, Postbus 2, NL-1755 ZG Petten (Netherlands); Sanda, Radian; Peinador, Miguel; Zerger, Benoit [JRC-IET: Institute for Energy and Transport of the Joint Research Centre of the European Commission, Postbus 2, NL-1755 ZG Petten (Netherlands); Negri, Patrice [IRSN: Institut de Radioprotection et de Sûreté Nucléaire (France); Wenke, Rainer [GRS: Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbH (Germany)

    2014-08-15

    Highlights: • The important role of Operating Experience Feedback is emphasised. • Events relating to cracks and leaks in the reactor coolant pressure boundary are analysed. • A methodology for event investigation is described. • Some illustrative results of the analysis of events for specific components are presented. - Abstract: The presence of cracks and leaks in the reactor coolant pressure boundary may jeopardise the safe operation of nuclear power plants. Analysis of cracks and leaks related events is an important task for the prevention of their recurrence, which should be performed in the context of activities on Operating Experience Feedback. In response to this concern, the EU Clearinghouse operated by the JRC-IET supports and develops technical and scientific work to disseminate the lessons learned from past operating experience. In particular, concerning cracks and leaks, the studies carried out in collaboration with IRSN and GRS have allowed to identify the most sensitive areas to degradation in the plant primary system and to elaborate recommendations for upgrading the maintenance, ageing management and inspection programmes. An overview of the methodology used in the analysis of cracks and leaks related events is presented in this paper, together with the relevant results obtained in the study.

  12. NJOY91, General ENDF/B Processing System for Reactor Design Problems

    International Nuclear Information System (INIS)

    MacFarlane, R.E.; Barrett, R.J.; Muir, D.W.; Boicourt, R.M.

    1997-01-01

    1 - Description of problem or function: The NJOY nuclear data processing system is a comprehensive computer code package for producing pointwise and multigroup neutron, photon, and charged particle cross sections from ENDF/B evaluated nuclear data. NJOY-89 is a substantial upgrade of the previous release. It includes photon production and photon interaction capabilities, heating calculations, covariance processing, and thermal scattering capabilities. It is capable of processing data in ENDF/B-4, ENDF/B-5, and ENDF/B-6 formats for evaluated data (to the extent that the latter have been frozen at the time of this release). NJOY-91.118: This is the last in the NJOY-91 series. It uses the same module structure as the earlier versions and its graphics options depend on DISSPLA. NJOY91.118 includes bug fixes, improvements in several modules, and some new capabilities. Information on the changes is included in the README file. A new test problem was added to test some ENDF/B-6 features, including Reich-Moore resonance reconstruction, energy-angle matrices in GROUPR, and energy-angle distributions in ACER. The 91.118 release is basically configured for UNIX. Short descriptions of the different modules follow: RECONR Reconstructs pointwise (energy-dependent) cross sections from ENDF/B resonance parameters and interpolation schemes. BROADR Doppler broadens and thins pointwise cross sections. UNRESR Computes effective self-shielded pointwise cross sections in the unresolved-resonance region. HEATR Generates pointwise heat production cross sections (KERMA factors) and radiation-damage-energy production cross sections. THERMR Produces incoherent inelastic energy-to-energy matrices for free or bound scatterers, coherent elastic cross sections for hexagonal materials, and incoherent elastic cross sections. GROUPR Generates self-shielded multigroup cross sections, group- to-group neutron scattering matrices, and photon production matrices from pointwise input. GAMINR Calculates

  13. Workers' Education in Industrialised Countries and Its Specific Problems in Relation to Development.

    Science.gov (United States)

    Labour Education, 1986

    1986-01-01

    Examines several problems that need to be addressed concerning world crisis: war, poverty, unemployment, overpopulation, environmental issues, and housing; developed versus developing countries; and social justice. The task for workers' education in relation to these problems is discussed. (CT)

  14. Malting and Brewing Industries Encounter Fusarium spp. Related Problems

    Directory of Open Access Journals (Sweden)

    Kristina Mastanjević

    2018-01-01

    Full Text Available Versatile microbiota are inevitably naturally present on cereals. Fungi, yeasts and bacteria and their metabolites all contribute to the quality and safety of the final products derived from most common beer cereals—barley and wheat. The microorganisms that are most often associated with the safety and quality of cereals for beer production belong to the Fusarium spp. They greatly influence yields from the field, and can modify and diminish economic success for farmers. However, the real problem is their harmful metabolites—mycotoxins—that affect the health of humans and animals. In the era of emerging analytical methodologies, the spectrum of known toxins originating from microorganisms that can pose a threat to humans has grown tremendously. Therefore, it is necessary to monitor microflora throughout the productive “barley to beer” chain and to act suppressive on the proliferation of unwanted microorganisms, before and during malting, preventing the occurrence of mycotoxins in final products and by-products. Multi-mycotoxin analyses are very advanced and useful tools for the assessment of product safety, and legislation should follow up and make some important changes to regulate as yet unregulated, but highly occurring, microbial toxins in malt and beer.

  15. [Behavioural problems and personality change related to cerebral amyloid angiopathy].

    Science.gov (United States)

    Gahr, Maximilian; Connemann, Bernhard J; Schönfeldt-Lecuona, Carlos

    2012-11-01

    Cerebral amyloid angiopathy (CAA) belongs to the group of amyloidoses that are characterized by the deposition of insoluble and tissue-damaging amyloid proteins. Spontaneous intracerebral hemorrhage is the common clinical presentation of CAA resulting from the degenerative effect of beta amyloid on the cerebral vascular system. Though CAA is rather a neurological disease psychiatric symptoms can occur and even dominate the clinical picture. A case report is presented in order to illustrate the association between CAA and psychiatric symptoms. We report the case of a 54-year-old female patient with radiologic references to a probable CAA and mild cognitive impairment who developed behavioural difficulties and personality change that necessitated a psychiatric treatment. Psychiatric symptoms were most likely due to CAA. CAA can be associated with psychiatric symptoms and hence should be considered in the treatment of elderly patients with behavioural problems or personality changes. Diagnostic neuroimaging and examination of cerebrospinal fluid is recommended. © Georg Thieme Verlag KG Stuttgart · New York.

  16. Report on safety related occurrences and reactor trips January 1 - June 30, 1984

    International Nuclear Information System (INIS)

    1984-01-01

    This is a systematically arranged report on all safety-related occurrences and reactor trips in Swedish nuclear power plants in operation during the period from January 1 to June 30 1984. It is based on the reports submitted by the utilities to the Swedish Nuclear Inspectorate according to Technical Specifications. Twice a year since 1974 the Inspectorate has issued a compilation on such reported occurrences and reactor trips. Starting with the compilation of the second half of 1982 some new features have been introduced. The most important change is that the volume of information has been increased. The full text, provided by the utilities when reporting the incidents, is now attached to the codified information and also the layout has been altered to facilitate reading. As in the previous reports the occurrences and reactor trips are arranged both alphabetically by facility name and chronologically by report number for each facility. Electricity generation charts for each facility are also presented. The primary purpose of this report is thus to present all the information furnished by the utilities when they submit their reports according to Technical Specifications. The only evaluation made by the Inspectorate is the categorization on the incidents. Like the previous reports this one also presents frequency of incidents as related to affected component, cause of incident etc. The difference is that only information reported by the utilities is used. This is the reason why a considerable proportion of the incidents are categorized as other component or other fault. Sometime in the future, however, the Inspectorate plants to put out a special report containing its own analyses of the most interesting events along with processed statistics and other information. (author)

  17. Some foundational problems in the special theory of relativity

    International Nuclear Information System (INIS)

    Jammer, M.

    1979-01-01

    Attention is drawn to some of the issues of the foundations of special relativity with the aim of contributing possibly to their clarification. Roemer's determination of the velocity of light is reviewed and important issues on the historical development of the theory outlined. The group-theoretical and light-geometrical approaches are discussed and the nature of length contraction considered. (Auth./C.F.)

  18. 10 CFR 72.108 - Spent fuel, high-level radioactive waste, or reactor-related greater than Class C waste...

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Spent fuel, high-level radioactive waste, or reactor... RADIOACTIVE WASTE, AND REACTOR-RELATED GREATER THAN CLASS C WASTE Siting Evaluation Factors § 72.108 Spent fuel, high-level radioactive waste, or reactor-related greater than Class C waste transportation. The...

  19. On a covariant 2+2 formulation of the initial value problem in general relativity

    International Nuclear Information System (INIS)

    Smallwood, J.

    1980-03-01

    The initial value problems in general relativity are considered from a geometrical standpoint with especial reference to the development of a covariant 2+2 formalism in which space-time is foliated by space-like 2-surfaces under the headings; the Cauchy problem in general relativity, the covariant 3+1 formulation of the Cauchy problem, characteristic and mixed initial value problems, on locally imbedding a family of null hypersurfaces, the 2+2 formalism, the 2+2 formulation of the Cauchy problem, the 2+2 formulation of the characteristic and mixed initial value problems, and a covariant Lagrangian 2+2 formulation. (U.K.)

  20. Italian position paper on the safety analysis of liquid metal fast breeder reactors as related to sodium fires. The PEC reactor

    International Nuclear Information System (INIS)

    Gerosa, A.

    1983-01-01

    To obtain a deep understanding of physical phenomena and engineering problems connected to sodium fires, and to optimize the utilization of human and financial resources available, CNEN (now ENEA) has decided to join the French Commissariat a l'Energie Atomique (CEA) in the realization of a Franco-Italian experimental programme on sodium fires, named ESMERALDA. As for design preventions for PEC reactor (a fast flux, liquid metal cooled, fuel element testing reactor) fundamental choices were made taking into account all available knowledge, but with particular reference to the results of CEA's previous experiments on sodium fires. More detailed design analysis will be possible in the future, based on experimental results coming from the ESMERALDA programme

  1. Evaluation of speedup of Monte Carlo calculations of two simple reactor physics problems coded for the GPU/CUDA environment

    International Nuclear Information System (INIS)

    Ding, Aiping; Liu, Tianyu; Liang, Chao; Ji, Wei; Shephard, Mark S.; Xu, X George; Brown, Forrest B.

    2011-01-01

    Monte Carlo simulation is ideally suited for solving Boltzmann neutron transport equation in inhomogeneous media. However, routine applications require the computation time to be reduced to hours and even minutes in a desktop system. The interest in adopting GPUs for Monte Carlo acceleration is rapidly mounting, fueled partially by the parallelism afforded by the latest GPU technologies and the challenge to perform full-size reactor core analysis on a routine basis. In this study, Monte Carlo codes for a fixed-source neutron transport problem and an eigenvalue/criticality problem were developed for CPU and GPU environments, respectively, to evaluate issues associated with computational speedup afforded by the use of GPUs. The results suggest that a speedup factor of 30 in Monte Carlo radiation transport of neutrons is within reach using the state-of-the-art GPU technologies. However, for the eigenvalue/criticality problem, the speedup was 8.5. In comparison, for a task of voxelizing unstructured mesh geometry that is more parallel in nature, the speedup of 45 was obtained. It was observed that, to date, most attempts to adopt GPUs for Monte Carlo acceleration were based on naïve implementations and have not yielded the level of anticipated gains. Successful implementation of Monte Carlo schemes for GPUs will likely require the development of an entirely new code. Given the prediction that future-generation GPU products will likely bring exponentially improved computing power and performances, innovative hardware and software solutions may make it possible to achieve full-core Monte Carlo calculation within one hour using a desktop computer system in a few years. (author)

  2. Optimal improvement of graphs related to nuclear safeguards problems

    International Nuclear Information System (INIS)

    Jacobsen, S.E.

    1977-08-01

    This report develops the methodology for optimally improving graphs related to nuclear safeguards issues. In particular, given a fixed number of dollars, the report provides a method for optimally allocating such dollars over the arcs of a weighted graph (the weights vary as a function of dollars spent on arcs) so as to improve the system effectiveness measure which is the shortest of all shortest paths to several targets. Arc weights can be either clock times or detection probabilities and the algorithm does not explicitly consider all paths to the targets

  3. [Trampoline-related injuries in children: an increasing problem].

    Science.gov (United States)

    Königshausen, M; Gothner, M; Kruppa, C; Dudda, M; Godry, H; Schildhauer, T A; Seybold, D

    2014-06-01

    The sales of recreational trampolines have increased during the past few years. Severe injuries are associated in part with trampoline sport in the domestic setting. Therefore, this study was conducted to confirm the hypothesis of an increase in trampoline-related injuries in conjunction with the increasing sales of recreational trampolines and to find out what kind of injuries are most frequent in this context. Between 01/1999 and 09/2013 all trampoline-related injuries of children (0-16 years of age) were assessed retrospectively. Only those cases were evaluated which described with certainty a trampoline-associated trauma. The fractures were considered separately and assigned to specific localisations. Additionally, accidents at home were differentiated from institutional accidents. Within the past 13 years and 9 months trampoline-related injuries were seen in 195 infants. Fractures were present in 83 cases (42 %). The average age was 10 ± 3.4 years (range: 2-16 years). Within first half of the observed time period (7½ years; 01/1999 to 06/2006) 73 cases were detected with a significantly increasing number of injuries up to 122 cases between 07/2006 and 09/2013 (7 years, 3 months), which corresponds to an increase of 67 % (p = 0,028). The vast majority of these injuries happened in the domestic setting (90 %, n = 175), whereas only 10 % (n = 20) of the traumas occurred in public institutions. In 102 children (52 %) the lower extremity was affected and in 51 patients (26 %) the upper extremity was involved (head/spine/pelvis: n = 42, 22 %). The upper extremity was primarily affected by fractures and dislocations (n = 38, 76 %). At the upper extremity there were more injuries requiring surgery in contrast to the lower extremity (n = 11) or cervical spine (n = 1). The underlying data show a significant increase of trampoline-related injuries within the past years. The upper extremity is the second most affected

  4. The problems of material pairs under the specific conditions of high-temperature reactors

    International Nuclear Information System (INIS)

    Schoening, J.

    1981-01-01

    This dissertation gives a detailed descirption of the problems of friction and solid lubrication of slide and ball bearings under HTR conditions. The first part is concerned with an analysis of established approaches for determining the friction factor and the development of a mathematical model on this basis, taking particular account of the following parameters. (1) Surface characteristics (peak-to-valley height, pressure angles of roughness elevations) and, (2) material properties of the friction partner (ductility, brittleness, crystal structure). The formula for friction factor thus arrived at incorporates the microscopic and sub-microscopic influence of the surface grain structure. In addition, the effects of elastic and plastic properties at the region of contact was studied. The derived equation is used to characterise frictional properties and enables a suitable and economic friction pair to be selected. The second part deals with the application of solid lubrication and the effect of the solid lubricant film on the mechanicsm and kinematics of ball bearings. In the final part of this investigation an evaluation of experimental results is carried out on the basis of the preceding theoretical studies in order to confirm the theoretical approach and to provide information of practical use on limits of application, cost details and aids to construction. (orig./IHOE) [de

  5. Numerical scheme for optimization of xenon transient processes in a reactor. Problem on fast response without a limitation for phase variables

    International Nuclear Information System (INIS)

    Gerasimov, A.S.

    1975-01-01

    A numerical diagram is suggested of minimizing a period of xenon transient process in the reactor without any limitation of xenon-135 concentration. The problem is solved with a computer in a point model. Pontryagin's maximum principle is used so as to check optimization of the transient process

  6. Detector point of view of reactor internal vibrations under Gaussian coloured random forces - the problem of fitting neutron noise experimental data

    International Nuclear Information System (INIS)

    Arnal, R.S.; Martin, G.V.; Gonzalez, J.L.M.-C.

    1988-01-01

    This paper studies the local vibrations of reactor components driven by Gaussian coloured and white forces, when nonlinear vibrations arise. We study also the important problem of noise sources, modelization and the noise propagation through the neutron field using the discrete ordinates transport theory. Finally, we study the effect of the neutron field upon the PSD (power spectral density) of the noise source and we analyse the problem of fitting neutron noise experimental data to perform pattern recognition analysis. (author)

  7. Economic assumptions for evaluating reactor-related options for managing plutonium

    International Nuclear Information System (INIS)

    Rothwell, G.

    1996-01-01

    This paper discusses the economic assumptions in the U.S. National Academy of Sciences' report, Management and Disposition of Excess Weapons Plutonium: Reactor-Related Options (1995). It reviews the Net Present Value approach for discounting and comparing the costs and benefits of reactor-related options. It argues that because risks associated with the returns to plutonium management are unlikely to be constant over time, it is preferable to use a real risk-free rate to discount cash flows and explicitly describe the probability distributions for costs and benefits, allowing decision makers to determine the risk premium of each option. As a baseline for comparison, it assumes that one economic benefit of changing the current plutonium management system is a reduction in on-going Surveillance and Maintenance (S and M) costs. This reduction in the present value of S and M costs can be compared with the discounted costs of each option. These costs include direct construction costs, indirect costs, operating costs minus revenues, and decontamination and decommissioning expenses. The paper also discusses how to conduct an uncertainty analysis. It finishes by summarizing conclusions and recommendations and discusses how these recommendations might apply to the evaluation of Russian plutonium management options. (author)

  8. Advanced Test Reactor (ATR) Facility 10CFR830 Safety Basis Related to Facility Experiments

    International Nuclear Information System (INIS)

    Tomberlin, T.A.

    2002-01-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) Advanced Test Reactor (ATR), a DOE Category A reactor, was designed to provide an irradiation test environment for conducting a variety of experiments. The ATR Safety Analysis Report, determined by DOE to meet the requirements of 10 CFR 830, Subpart B, provides versatility in types of experiments that may be conducted. This paper addresses two general types of experiments in the ATR facility and how safety analyses for experiments are related to the ATR safety basis. One type of experiment is more routine and generally represents greater risks; therefore this type of experiment is addressed with more detail in the safety basis. This allows individual safety analyses for these experiments to be more routine and repetitive. The second type of experiment is less defined and is permitted under more general controls. Therefore, individual safety analyses for the second type of experiment tend to be more unique from experiment to experiment. Experiments are also discussed relative to ''major modifications'' and DOE-STD-1027-92. Application of the USQ process to ATR experiments is also discussed

  9. Report on safety related occurrences and reactor trips January 1 - June 30, 1985

    International Nuclear Information System (INIS)

    1986-01-01

    This is a systematically arranged report on all safety-related occurrences and reacotr trips in Swedish nuclear power plants in operation during the period from January 1 to June 30 1985. It is based on the reports submitted by the utilities to the Swedish Nuclear power Inspectorate according to Technical Specifications. Twice a year since 1974 the Inspectorate has issued a compilation on such reported occurrences and reactor trips. Starting with the compilation of the second half of 1982 some new features have been introduced. The most important change is that the volume of information has been increased. The full test, provided by the utilities when reporting the incidents, is now attached to the codified information and also the layout has been altered to facilitate reading. As in the previous reports the occurrences and reactor trips are arranged both alphabetically by facility name and chronologically by report number for each facility. Electricity generation charts for each facility are also presented. The primary purpose of this report is thus to present all the information furnished by utlities when they submit their reports according the Technical Specifications. The only evaluation made by the Inspecotrate is the categorization on the incidents. Like the previous reports this one also presents frequency of incidents as related to affected component, cause of incident etc. The difference is that only information reported by the utilities is used. This is the reason why a considerable proportion of the incidents are categorized as 'other fault'. (author)

  10. Love and the commitment problem in romantic relations and friendship.

    Science.gov (United States)

    Gonzaga, G C; Keltner, D; Londahl, E A; Smith, M D

    2001-08-01

    On the basis of the proposition that love promotes commitment, the authors predicted that love would motivate approach, have a distinct signal, and correlate with commitment-enhancing processes when relationships are threatened. The authors studied romantic partners and adolescent opposite-sex friends during interactions that elicited love and threatened the bond. As expected, the experience of love correlated with approach-related states (desire, sympathy). Providing evidence for a nonverbal display of love, four affiliation cues (head nods, Duchenne smiles, gesticulation, forward leans) correlated with self-reports and partner estimates of love. Finally, the experience and display of love correlated with commitment-enhancing processes (e.g., constructive conflict resolution, perceived trust) when the relationship was threatened. Discussion focused on love, positive emotion, and relationships.

  11. Firework-related childhood injuries in Greece: a national problem.

    Science.gov (United States)

    Vassilia, Konte; Eleni, Petridou; Dimitrios, Trichopoulos

    2004-03-01

    During a 5-year period, out of 110066 children with injuries recorded in the Greek Emergency Department Injury Surveillance System (EDISS), 91 had firework-related injuries. Descriptive analyses and the Barrell matrix were used to determine risk factors and extrapolated national firework childhood injury figures were calculated. The estimated annual incidence of childhood firework injuries treated in the emergency departments of hospitals countrywide, was 7 per 100000 children years. Seventy percent of injuries concerned older children (10-14 years), mostly boys with self-inflicted injuries, whereas girls suffered injuries as bystanders. A sharp peak in spring was noted, when the Greek Orthodox Easter is celebrated. Illicitly sold fireworks caused most injuries, but in eight instances homemade firecrackers were responsible.

  12. Normative Beliefs, Expectancies, and Alcohol-Related Problems among College Students; Implications for Theory and Practice.

    Science.gov (United States)

    Fearnow-Kenny, Melodie D.; Wyrick, David L.; Hansen, William B.; Dyreg, Doug; Beau, Dan B.

    2001-01-01

    Investigation (1) examined interrelations among normative beliefs, alcohol expectancies, and alcohol-related problems, and (2) investigated whether alcohol-related expectancies mediate associations between normative beliefs and alcohol-related problems. Analyses revealed that alcohol expectancies mediate the relationship between normative beliefs…

  13. Review of activities of the Commission of the European Communities relating to fast reactors in 1988

    International Nuclear Information System (INIS)

    Balz, W.

    1989-01-01

    The Commission of the European Communities (CEC) is performing fast reactor activities in two areas: (1) co-ordination and harmonization and (2) research. Co-ordination and harmonization activities are essentially carried out in the frame of the Fast Reactor Co-ordinating Committee (FRCC). At present CEC is examining possible support schemes which include a contribution to R-D and/or to a EFR design effort. In line with the current CEC R-D activities a possible research support would be in the field of safety. Round robins on the determination of residual stress in cold worked materials and on the stress relaxation properties of austenitic stainless steels were accomplished. Studies were performed on high cycle fatigue of austenitic stainless and on stress rupture properties of 9-12 Cr steels. The work performed at the Ispra establishment is related to LMFBR safety, while the activities carried out at Karlsruhe concern essentially fast breeder fuels. Safety research at Ispra comprises essentially the investigation and analysis of severe accident phenomena under three main projects: FARO, EAC and PAHR in-pile. The short-term nitride irradiation experiments NILOC 1 and 2 were analysed in detail and compared with the previous short-term carbide irradiations CARLO and CARRO which had been performed under partly identical conditions as NILOC 2. In the context of an industrial project to transmute long-lived actinides in nuclear waste into short-lived fission products in a dedicated fast reactor, a study was launched to determine the thermodynamics and the metallurgical characteristics of alloys of uranium-plutonium-zirconium with various amounts of the minor actinides neptunium, americium, and curium. First experimental data on the specific heat of refractory metals and UO 2 at and above their melting temperatures were obtained with newly developed equipment using laser pulse heating and ultra fast multi-wavelength pyrometry. The results thus obtained will be input data

  14. Emotional pain: surviving mental health problems related to childhood experiences.

    Science.gov (United States)

    Holm, A L; Bégat, I; Severinsson, E

    2009-09-01

    Emotional pain is described as intense by women who suffer from borderline personality disorder (BPD), and a high prevalence of reported childhood abuse was found in the literature and in research. The aim of this study was to explore the experiences of women suffering from BPD with focus on emotional pain related to childhood. An explorative design was used. Data were collected from in-depth interviews consisting of women suffering from BPD (n = 13) and an interpretive content analysis was used to analyse the text. The findings revealed two main themes: 'Power' and 'Assessment of vulnerability'. The main theme 'Power' resulted in two categories: 'Surviving the feeling of being forced' and 'Surviving the feeling of having to assume responsibility'. The other main theme 'Assessment of vulnerability' had two categories: 'Surviving the feeling of being victimized' and 'Surviving the feeling of not being loved'. The findings suggest that nursing care need to develop an understanding of how these women endure their emotional pain, and try to survive as fighting spirits and how struggling became their way of life.

  15. Uses of ionizing radiation and medical-care-related problems

    International Nuclear Information System (INIS)

    Smathers, J.B.

    1988-01-01

    The uses of ionizing radiation in medicine are currently undergoing changes due to at least four major influences: (1) the constantly changing public perception of the hazards of radiation, (2) continuing technical innovation and development in equipment, (3) the imposition of diagnosis-related group funding by government health-care funding agencies, and (4) an increase in the average age of the U.S. population. The combined effect of these influences will probably result in a major increase in biplanar fluoroscopic examinations to support nonsurgical approaches such as percutaneous transluminal coronary angioplasty, percutaneous transluminal neuroembolism, and lithotripsy (the fracturing of kidney stones). As some of these examinations can result in 1.5 h of fluoroscopy, major doses to the patient and to the clinical staff can be expected. In addition, improved diagnostic techniques, such as using positron emission tomography (a combination of biochemistry and positron-emitting isotopes), can be expected to increase the number of small cyclotrons installed in medical centers. Counteracting these increases in radiation exposure is the development of digital radiography, which generally results in a lowering of the dose per diagnostic procedure. In the realm of therapeutic uses, one can expect higher-energy treatment accelerators, more patients being released from the hospital on therapeutic doses of isotopes, and a potential acceptance of neutron therapy as a cancer treatment modality. The latter treatment may take the form of boron capture therapy, 252Cf implant therapy, or external beam therapy using high-energy cyclotrons and the p,Be or the d,Be reaction to create the neutrons

  16. A study of selected problems related to accidental process fires

    Energy Technology Data Exchange (ETDEWEB)

    Drange, Leiv Anfin

    2011-01-15

    predicted a correct flame length, but estimated a slightly shorter lift-off distance; the end part of the KFX-flame was more influenced by buoyancy and deviated some from that of the experiment; the measurements showed more irregular shaped temperature fields compared to the simulated; the measurements showed larger fluctuations in the temperature fields compared to the simulated; the maximum measured radiative heat flux inside the flame was 185kW/m2. The maximum simulated radiative heat flux was 193kW/m2, representing a deviation of 4.3%; the maximum measured total heat flux was 256kW/m2. A steel cylinder of radius 160mm was placed at various positions in the jet, and the relative heat transfer was assessed by means of thermocouples placed radially inside the cylinder. This work showed that: convection is the major contributor to the total heat transfer from a turbulent jet flame to a steel cylinder impinged by the flame; the largest rate of heat transfer is at the side facing the flame, i.e no high levels of turbulence induced thermal loading could be detected at the back; the heat transfer coefficient, h, is a function of the velocity of the gas flow relative to the impinged object The stability of ignited propane gas jets, discharged from circular cross section outlets of varying diameters and inclinations were examined. This resulted in: a model, with an accuracy of 0.89, that predicts the upper and lower blowout limits for propane in gas phase, as well as a critical outlet diameter of 14mm; no observations were made indicating that the outlet inclination has any effect on the blowout limits The heat attenuation in water spray in a full scale offshore flare situation was examined by applying a known model for calculations and comparing with measurements. The result of this work was: the model predictions slightly under estimated the capacity of the water curtain. There were, however, uncertainties regarding the water curtain properties, and more detailed measurements

  17. Assessment of computer-related health problems among post-graduate nursing students.

    Science.gov (United States)

    Khan, Shaheen Akhtar; Sharma, Veena

    2013-01-01

    The study was conducted to assess computer-related health problems among post-graduate nursing students and to develop a Self Instructional Module for prevention of computer-related health problems in a selected university situated in Delhi. A descriptive survey with co-relational design was adopted. A total of 97 samples were selected from different faculties of Jamia Hamdard by multi stage sampling with systematic random sampling technique. Among post-graduate students, majority of sample subjects had average compliance with computer-related ergonomics principles. As regards computer related health problems, majority of post graduate students had moderate computer-related health problems, Self Instructional Module developed for prevention of computer-related health problems was found to be acceptable by the post-graduate students.

  18. Moisture and Home Energy Conservation: How to Detect, Solve and Avoid Related Problems.

    Science.gov (United States)

    National Center for Appropriate Technology, Butte, MT.

    Moisture problems are identified as an important element in home energy conservation programs. A systematic approach to understanding, recognizing, solving, and preventing moisture-related problems is offered in this four-section report. Section I examines the root of moisture problems. Section II discusses symptoms and causes of excess moisture…

  19. Human Performance on the Traveling Salesman and Related Problems: A Review

    Science.gov (United States)

    MacGregor, James N.; Chu, Yun

    2011-01-01

    The article provides a review of recent research on human performance on the traveling salesman problem (TSP) and related combinatorial optimization problems. We discuss what combinatorial optimization problems are, why they are important, and why they may be of interest to cognitive scientists. We next describe the main characteristics of human…

  20. Radiochemical problems of radiation chemical synthesis in n, γ-field of nuclear reactor

    International Nuclear Information System (INIS)

    Mironov, V.P.; Frejdus, N.V.; Bugaenko, L.T.; Kalyazin, E.P.; Petryaev, E.P.

    1981-01-01

    A wide applicability of products of radiation chemical synthesis (RCS), using n, γ-irradiation, is limited by possible contamination of the latter with long-lived radioactive isotopes of chemical elements included in the composition of the reagent and compounds syntesized (chemically non-separable radionuclides - CNR). A technique of the determination of the limit accumulation CNR on the basis of radiation chemical parameters of the synthesis (radiation-chemical yield, the dose rate absorbed, singleness of purpose of RCS etc.) and radiochemical parameters of formation and accumulation of CNR (radiochemical yields of CNR in the products of radiolysis, neutron fluence, the reagent purity etc.) is suggested. The radiochemical evaluation of CNR accumulation (tritium and carbon-14), formed at the expense of activation with neutrons of chemical elements of water and organic substances, consisting of hydrogen, carbon and oxygen has shown that at relatively low yields of final products (> or approximately 3 molecules/100 eV) no accumulation of radionuclides in concentrations reaching the average admissible concentration takes place [ru

  1. Predictors of intimate partner problem-related suicides among suicide decedents in Kentucky

    Directory of Open Access Journals (Sweden)

    Ashley L. Comiford

    2016-07-01

    Full Text Available BACKGROUND: Suicide is the 10th leading cause of death in the United States. Furthermore, intimate partner problems are amid the top precipitating circumstances among suicide decedents. The aim of this study was to determine circumstantial associations of intimate partner problem-related suicides in suicide decedents in Kentucky. METHODS: All suicides that were reported to the Kentucky Violent Death Reporting System between 2005 and 2012 were eligible for this study. Multiple logistic regression was used to explore predictors (precipitating health-related problems, life stressors, and criminal/legal issues of intimate partner problem-related suicides. RESULTS: Of the 4,754 suicides, included in this study, approximately 17% had intimate partner problems prior to suicide. In the adjusted analysis, mental health issues, alcohol problems, history of suicides attempts, suicides precipitated by another crime, and other legal problems increased the odds of having an intimate partner-related suicide. However, having physical health problems, prior to the suicide, decreased the odds of intimate partner-related suicide. CONCLUSIONS: These results provide insight for the development of suicide interventions for individuals with intimate partner problems by targeting risk factors that are prevalent among this population. Moreover, these results may help marriage/relationship and/or family/divorce court representatives identify individuals with intimate partner problems more at risk for suicide and alleviate the influence these suicide risk factors have on individuals experiencing Intimate partner problems.

  2. The problem of adequacy in skin dosimetry for the case of a nuclear reactor emergency and for occupational exposure

    International Nuclear Information System (INIS)

    Osanov, D.

    1991-01-01

    The requirement for satisfactory skin dosimetry is, briefly, that the measured dosimetric values should be applicable for further unambiguous prediction of the radiation-induced effects. To fit these requirements the dose limits and actual dose burdens should be concerned with those target skin structures that are primarily responsible for biological effects. The problem of adequate skin dosimetry is here considered for the two most important situations: (1) for normal operation of nuclear power plants, and (2) for a nuclear reactor emergency. A method for determination of the absorbed dose of beta radiation in the surface tissues of the human body from a flat source produced by radionuclides accumulated on the ground surface is presented. Skin dose estimation techniques and actual values of personnel skin doses are also presented, as well as the application of such dose data in predicting the consequences of the irradiation. The principles of emergency and conventional skin dosemeter construction fulfilling the requirements for adequacy and for the measurement of the dose limits for occupational irradiation of the skin are discussed. (author)

  3. Applications of decision analysis and related techniques to industrial engineering problems at KSC

    Science.gov (United States)

    Evans, Gerald W.

    1995-01-01

    This report provides: (1) a discussion of the origination of decision analysis problems (well-structured problems) from ill-structured problems; (2) a review of the various methodologies and software packages for decision analysis and related problem areas; (3) a discussion of how the characteristics of a decision analysis problem affect the choice of modeling methodologies, thus providing a guide as to when to choose a particular methodology; and (4) examples of applications of decision analysis to particular problems encountered by the IE Group at KSC. With respect to the specific applications at KSC, particular emphasis is placed on the use of the Demos software package (Lumina Decision Systems, 1993).

  4. Scaling of reactor cavity wall loads and stresses

    International Nuclear Information System (INIS)

    Bohachevsky, I.O.

    1977-11-01

    Scalings of reactor cavity wall loads and stresses are determined by deriving an analytic expression in terms of relevant parameters for each loading induced in the reactor cavity walls by fuel pellet microexplosion and by deriving associated expressions relating resulting stresses to shell thicknesses. Also identified are problems that require additional investigations to obtain satisfactory explicit stress estimates for the reactor cavity walls

  5. Drug-related problems identified in medication reviews by Australian pharmacists

    DEFF Research Database (Denmark)

    Stafford, Andrew C; Tenni, Peter C; Peterson, Gregory M

    2009-01-01

    OBJECTIVE: In Australia, accredited pharmacists perform medication reviews for patients to identify and resolve drug-related problems. We analysed the drug-related problems identified in reviews for both home-dwelling and residential care-facility patients. The objective of this study was to exam......OBJECTIVE: In Australia, accredited pharmacists perform medication reviews for patients to identify and resolve drug-related problems. We analysed the drug-related problems identified in reviews for both home-dwelling and residential care-facility patients. The objective of this study....... These reviews had been self-selected by pharmacists and submitted as part of the reaccreditation process to the primary body responsible for accrediting Australian pharmacists to perform medication reviews. The drug-related problems identified in each review were classified by type and drugs involved. MAIN...... OUTCOME MEASURE: The number and nature of drug-related problems identified in pharmacist-conducted medication reviews. RESULTS: There were 1,038 drug-related problems identified in 234 medication reviews (mean 4.6 (+/-2.2) problems per review). The number of problems was higher (4.9 +/- 2.0 vs. 3.9 +/- 2...

  6. Prevalence of work-related health problems among providers of car ...

    African Journals Online (AJOL)

    Prevalence of work-related health problems among providers of car battery ... the use of personal protective devices and safety measures should be promoted. Keywords: Prevalence, work-related, battery chargers, occupational health, Nigeria ...

  7. R and D relative to the serious accidents in the PWR type reactors: assessment and perspectives; R and D relative aux accidents graves dans les reacteurs a eau pressurisee: bilan et perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Bentaib, A.; Bonneville, H.; Caroli, H.; Chaumont, B.; Clement, B.; Cranga, M.; Koundy, V.; Laurent, B.; Micaelli, J.C.; Meignen, R.; Pichereau, F.; Plassart, D.; Van-Dorsselaere, P. [Institut de Radioprotection et de Surete Nucleaire (IRSN), 92 - Clamart (France); Ducros, G.; Journeau, Ch.; Magallon, D. [CEA Cadarache, 13 - Saint Paul lez Durance (France); Durin, M.; Studer, E. [CEA Saclay 91 - Gif sur Yvette (France); Seiler, J.M. [CEA Grenoble, 38 (France); Ranval, W. [Electricite de France (EDF), 75 - Paris (France)

    2006-07-01

    This document presents the current state of the research relative to the grave accidents realized in France and abroad. It aims at giving the most exhaustive possible and objective vision of this original field of research. He allows to contribute to the identification and to the hierarchical organization of the needs of R and D, this hierarchical organization in front of, naturally, to be completed by a strong lighting on needs in terms of safety analyses associated with the different risks and the physical phenomena, in particular with the support of probability evaluations of safety level 2, whose the level of sharpness must be sufficient not to hide, by construction, physical phenomena of which the limited knowledge leads to important uncertainties. Let us note that neither the safety analyses, nor the E.P.S. 2 are presented in this document. This report presents the physical phenomena which can arise during a grave accident, in the reactor vessel and in the reactor containment, their chain and the means allowing to ease the effects. The corresponding scenarios are presented to the chapter 2. The chapter 3 is dedicated to the progress of the accident in the reactor vessel; the degradation of the core in reactor vessel (3.1), the behavior of the corium in bottom of reactor vessel (3.2) the break of the reactor vessel (3.3) and the fusion in pressure (3.4) are thus handled there. The chapter 4 concerns the phenomena which can lead to a premature failure of the containment, namely the direct heating of gases of the containment (4.1), the hydrogen risk (4.2) and the vapor explosion (4.3). The phenomenon which can lead to a delayed failure from the containment, namely the interaction corium-concrete, is approached on the chapter 5. The chapter 6 is dedicated to the problems connected to the keeping back and to the corium cooling in reactor vessel and out of reactor vessel, namely the keeping back in reactor vessel by re-flooding of the primary circuit or by re

  8. Regulatory instrument review: Management of aging of LWR [light water reactor] major safety-related components

    International Nuclear Information System (INIS)

    Werry, E.V.

    1990-10-01

    This report comprises Volume 1 of a review of US nuclear plant regulatory instruments to determine the amount and kind of information they contain on managing the aging of safety-related components in US nuclear power plants. The review was conducted for the US Nuclear Regulatory Commission (NRC) by the Pacific Northwest Laboratory (PNL) under the NRC Nuclear Plant Aging Research (NPAR) Program. Eight selected regulatory instruments, e.g., NRC Regulatory Guides and the Code of Federal Regulations, were reviewed for safety-related information on five selected components: reactor pressure vessels, steam generators, primary piping, pressurizers, and emergency diesel generators. Volume 2 will be concluded in FY 1991 and will also cover selected major safety-related components, e.g., pumps, valves and cables. The focus of the review was on 26 NPAR-defined safety-related aging issues, including examination, inspection, and maintenance and repair; excessive/harsh testing; and irradiation embrittlement. The major conclusion of the review is that safety-related regulatory instruments do provide implicit guidance for aging management, but include little explicit guidance. The major recommendation is that the instruments be revised or augmented to explicitly address the management of aging

  9. Problems of Development of the Turkish-Iranian Relations after Islamic Revolution of 1979

    Directory of Open Access Journals (Sweden)

    A V Suleymanov

    2013-12-01

    Full Text Available Problems of development of the Turkish-Iranian relations after Islamic revolution of 1979 are considered in the article. Based on comparative, historical and system methods, the author analyzes in details ideological and political problems of mutual relations of the subsequent periods, their characteristic and distinctive features.

  10. Ethnic Differences in Relations between Family Process and Child Internalizing Problems

    Science.gov (United States)

    Vendlinski, Matthew; Silk, Jennifer S.; Shaw, Daniel S.; Lane, Tonya J.

    2006-01-01

    Background: Family process variables have been linked to child problem behavior, but recent research suggests that child ethnicity may moderate relations between family process and child outcomes. The current study examined how ethnicity moderates relations between parent conflict, parent-child relationship quality, and internalizing problems.…

  11. Parenting and Children's Adjustment Problems: The Mediating Role of Self-Esteem and Peer Relations

    Science.gov (United States)

    Georgiou, Nicos A.; Stavrinides, Panayiotis; Georgiou, Stelios

    2016-01-01

    The aim of this study was to investigate the impact of parental and personal characteristics on children's internalizing/externalizing problems. Further, this study aimed to examine personal characteristics (self-esteem, peer relations) as mediators in the relation between parenting and internalizing/externalizing problems. In order to address…

  12. Microstructural characteristics of PWR [pressurized water reactor] spent fuel relative to its leaching behavior

    International Nuclear Information System (INIS)

    Wilson, C.N.

    1986-01-01

    Microstructural, compositional and thermochemical properties of spent nuclear fuel are discussed relative to its potential performance as a high-level waste form under proposed Nevada Nuclear Waste Storage Investigations Project tuff repository conditions. Pressurized water reactor spent fuel specimens with various artificially induced cladding defects were leach tested in deionized water and in a reference tuff groundwater under ambient hot cell air and temperature conditions. Greater fractional actinide release was observed with bare fuel than with clad fuel leached through a cladding defect. Congruent actinide release and preferential release of cesium and technetium were observed in both water types. Selected summary radionuclide release data are presented and correlated to pre- and post-test microstructural characterization data

  13. The measurement of neutron and neutron induced photon spectra in fusion reactor related assemblies

    CERN Document Server

    Unholzer, S; Klein, H; Seidel, K

    2002-01-01

    The spectral neutron and photon fluence (or flux) measured outside and inside of assemblies related to fusion reactor constructions are basic quantities of fusion neutronics. The comparison of measured spectra with the results of MCNP neutron and photon transport calculations allows a crucial test of evaluated nuclear data as generally used in fusion applications to be carried out. The experiments concern mixed neutron/photon fields with about the same intensity of the two components. An NE-213 scintillation spectrometer, well described by response matrices for both neutrons and photons, is used as proton-recoil and Compton spectrometer. The experiments described here in more detail address the background problematic of two applications, an iron benchmark experiment with an ns-pulsed neutron source and a deep penetration mock-up experiment for the investigation of the ITER in-board shield system. The measured spectral neutron and photon fluences are compared with spectra calculated with the MCNP code on the b...

  14. Prospects for and problems of using light-water supercritical-pressure coolant in nuclear reactors in order to increase the efficiency of the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Alekseev, P. N.; Semchenkov, Yu. M.; Sedov, A. A.; Subbotin, S. A.; Chibinyaev, A. V.

    2011-01-01

    Trends in the development of the power sector of the Russian and world power industries both at present time and in the near future are analyzed. Trends in the rise of prices for reserves of fossil and nuclear fuels used for electricity production are compared. An analysis of the competitiveness of electricity production at nuclear power plants as compared to the competitiveness of electricity produced at coal-fired and natural-gas-fired thermal power plants is performed. The efficiency of the open nuclear fuel cycle and various versions of the closed nuclear fuel cycle is discussed. The requirements on light-water reactors under the scenario of dynamic development of the nuclear power industry in Russia are determined. Results of analyzing the efficiency of fuel utilization for various versions of vessel-type light-water reactors with supercritical coolant are given. Advantages and problems of reactors with supercritical-pressure water are listed.

  15. Cost-benefit evaluation of containment related engineered safety features of Indian pressurized heavy water reactors

    International Nuclear Information System (INIS)

    Bajaj, S.S.; Bhawal, R.N.; Rustagi, R.S.

    1984-01-01

    The typical containment system for a commercial nuclear reactor uses several engineered safety features to achieve its objective of limiting the release of radioactive fission products to the environment in the event of postulated accident conditions. The design of containment systems and associated features for Indian Pressurized Heavy Water Reactors (PHWRs) has undergone progressive improvement in successive projects. In particular, the current design adopted for the Narora Atomic Power Project (NAPP) has seen several notable improvements. The paper reports on a cost-benefit study in respect of three containment related engineered safety features and subsystems of NAPP, viz. (i) secondary containment envelope, (ii) primary containment filtration and pump-back system, and (iii) secondary containment filtration, recirculation and purge system. The effect of each of these systems in reducing the environmental releases of radioactivity following a design basis accident is presented. The corresponding reduction in population exposure and the associated monetary value of this reduction in exposure are also given. The costs of the features and subsystem under consideration are then compared with the monetary value of the exposures saved, as well as other non-quantified benefits, to arrive at conclusions regarding the usefulness of each subsystem. This study clearly establishes for the secondary containment envelope the benefit in terms of reduction in public exposure giving a quantitative justification for the costs involved. In the case of the other two subsystems, which involve relatively low costs, while all benefits have not been quantified, their desirability is justified on qualitative considerations. It is concluded that the engineered safety features adopted in the current containment system design of Indian PHWRs contribute to reducing radiation exposures during accident conditions in accordance with the ALARA ('as low as reasonably achievable') principle

  16. International Conference on Fast Reactors and Related Fuel Cycles: Safe Technologies and Sustainable Scenarios (FR13). Presentations

    International Nuclear Information System (INIS)

    2013-01-01

    The conference, which was held from 4 to 7 of March 2013 in Paris, provided a forum to exchange information on national and international programmes, and more generally new developments and experience, in the field of fast reactors and related fuel cycle technologies. A first goal was to identify and discuss strategic and technical options that have been proposed by individual countries or companies. Another goal was to promote the development of fast reactors and related fuel cycle technologies in a safe, proliferation resistant and economic way. A third goal was to identify gaps and key issues that need to be addressed in relation to the industrial deployment of fast reactors with a closed fuel cycle. A fourth goal was to engage young scientists and engineers in this field, in particular with sustainability, innovation, simulation, safety, economics and public acceptance

  17. Comparative analysis of results between CASMO, MCNP and Serpent for a suite of Benchmark problems on BWR reactors; Analisis comparativo de resultados entre CASMO, MCNP y SERPENT para una suite de problemas Benchmark en reactores BWR

    Energy Technology Data Exchange (ETDEWEB)

    Xolocostli M, J. V.; Vargas E, S.; Gomez T, A. M. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Reyes F, M. del C.; Del Valle G, E., E-mail: vicente.xolocostli@inin.gob.mx [IPN, Escuela Superior de Fisica y Matematicas, UP - Adolfo Lopez Mateos, Edif. 9, 07738 Mexico D. F. (Mexico)

    2014-10-15

    In this paper a comparison is made in analyzing the suite of Benchmark problems for reactors type BWR between CASMO-4, MCNP6 and Serpent code. The Benchmark problem consists of two different geometries: a fuel cell of a pin and assembly type BWR. To facilitate the study of reactors physics in the fuel pin their nuclear characteristics are provided to detail, such as burnt dependence, the reactivity of selected nuclide, etc. With respect to the fuel assembly, the presented results are regarding to infinite multiplication factor for burning different steps and different vacuum conditions. Making the analysis of this set of Benchmark problems provides comprehensive test problems for the next fuels generation of BWR reactors with high extended burned. It is important to note that when making this comparison the purpose is to validate the methodologies used in modeling for different operating conditions, if the case is of other BWR assembly. The results will be within a range with some uncertainty, considering that does not depend on code that is used. Escuela Superior de Fisica y Matematicas of Instituto Politecnico Nacional (IPN (Mexico) has accumulated some experience in using Serpent, due to the potential of this code over other commercial codes such as CASMO and MCNP. The obtained results for the infinite multiplication factor are encouraging and motivate the studies to continue with the generation of the X S of a core to a next step a respective nuclear data library is constructed and this can be used by codes developed as part of the development project of the Mexican Analysis Platform of Nuclear Reactors AZTLAN. (Author)

  18. Materials problems related to the core catcher of sodium cooled reactors

    International Nuclear Information System (INIS)

    Goetzmann, O.

    1975-05-01

    There are in principal two possible solutions for the external core catcher as far as materials are concerned. 1) A barrier consisting of a material with a high melting point, 2) a tray of comparatively low melting material with a high solubility for the fuel. In case of the first concept one has to look for materials whose melting temperatures are above the temperature of the molten core. Based on metallurgical reasons it seems very likely that the molten core does not exceed a temperature in the range between 2,500 and 2,800 0 C. Due to the compatibility situation with the molten core only a few high melting oxides will be suitable as liner materials for a core catcher. In the second case basalt or concrete, if free of water and lime, are suitable materials. Graphite is a high melting material, however, due to its behaviour with the molten core it should be listed under the second group. By the reaction of graphite with the core materials the melt can be kept liquid down to temperatures of around 1,100 0 C. The evolution of CO by this reaction should be supportable. It is an endothermal reaction. Experiments on the behaviour of core catcher materials have shown that sodium is capable of penetrating into sintered bodies of UO 2 with densities of 90% TD at temperatures higher than 200 0 C. This may lead to the desintegration of these bodies. The exposure to moist air has not done much harm to UO 2 pellets of densities from 80 to 90% TD. Even after one year of exposure, swelling or desintegration could not be observed. Sodium is also capable of penetrating into bodies of synthetic carbon and graphite. Only well graphitized material will not be destroyed. (orig.) [de

  19. Two important safety-related verification tests in the design of Qinshan NPP 600 MWe reactor

    International Nuclear Information System (INIS)

    Li Pengzhou; Li Tianyong; Yu Danping; Sun Lei

    2005-01-01

    This paper summarizes two most important verification tests performed in the design of reactor of Qinshan NPP Phase II: seismic qualification test of control rod drive line (CRDL), flow-induced vibration test of reactor internals both in 1:5 scaled model and on-site measurement during heat function testing (HFT). Both qualification tests proved that the structural design of the reactor has large safety margin. (authors)

  20. Safety and authorizations relating to the use of new fuel in research reactors

    International Nuclear Information System (INIS)

    Niel, J.-C.; Abou Yehia, H.

    1999-01-01

    After giving a brief reminder of the procedure applied in France for granting licences to modify research reactors, we outline in this paper the main safety aspects associated with using new fuel in these reactors. Finally, by way of an example, we focus on the procedure followed for converting the cores of the OSIRIS (70 MW) and ISIS (700 kW) reactors to U 3 Si 2 Al fuel and the conclusions of the corresponding safety assessments. (author)